The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
Estimated average burden
hours per response: 23.8
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
3M CO. COM 88579Y101 3,073 18,692 SH   SOLE   0 0 18,692
ABBOTT LABORATORIES COM 002824100 7,808 93,323 SH   SOLE   0 0 93,323
ABBVIE INC COM 00287Y109 1,403 18,526 SH   SOLE   0 0 18,526
ADOBE SYSTEMS INCORPORATED COM 00724F101 3,995 14,461 SH   SOLE   0 0 14,461
AIR PRODUCTS & CHEMICALS COM 009158106 304 1,368 SH   SOLE   0 0 1,368
ALLSTATE CORPORATION COM 020002101 705 6,483 SH   SOLE   0 0 6,483
ALPHABET INC NON-VOTING CL C COM 02079K107 7,813 6,409 SH   SOLE   0 0 6,409
ALPHABET INC VOTING CL A COM 02079K305 598 490 SH   SOLE   0 0 490
AMAZON.COM INC COM 023135106 7,563 4,357 SH   SOLE   0 0 4,357
AMERICAN ELECTRIC POWER COM 025537101 244 2,606 SH   SOLE   0 0 2,606
AMERICAN EXPRESS INC COM 025816109 3,314 28,020 SH   SOLE   0 0 28,020
AMGEN INC COM 031162100 1,003 5,183 SH   SOLE   0 0 5,183
APPLE INC COM 037833100 9,594 42,837 SH   SOLE   0 0 42,837
AQUA AMERICA COM 03836W103 7,395 164,949 SH   SOLE   0 0 164,949
ARCHER DANIELS MIDLAND CO COM 039483102 1,022 24,876 SH   SOLE   0 0 24,876
AT&T CORP NEW COM 00206R102 2,280 60,253 SH   SOLE   0 0 60,253
ATMOS ENERGY CORP COM 049560105 2,032 17,840 SH   SOLE   0 0 17,840
BALL CORP COM 058498106 284 3,900 SH   SOLE   0 0 3,900
BANK OF AMERICA COM 060505104 1,207 41,367 SH   SOLE   0 0 41,367
BANK OF NEW YORK MELLON CORP COM 064058100 912 20,179 SH   SOLE   0 0 20,179
BECTON DICKINSON COM 075887109 10,909 43,127 SH   SOLE   0 0 43,127
BERKSHIRE HATHAWAY INC DEL CLA COM 084670108 4,054 13 SH   SOLE   0 0 13
BERKSHIRE HATHAWAY INC DEL CLA COM 084670702 730 3,510 SH   SOLE   0 0 3,510
BOEING COM 097023105 3,747 9,848 SH   SOLE   0 0 9,848
BP PLC SPONS ADR COM 055622104 266 7,000 SH   SOLE   0 0 7,000
BRISTOL-MYERS SQUIBB COMPANY COM 110122108 813 16,023 SH   SOLE   0 0 16,023
C S X CORPORATION COM 126408103 485 7,000 SH   SOLE   0 0 7,000
CABLE ONE INC COM 12685J105 473 377 SH   SOLE   0 0 377
CATERPILLAR INCORPORATED COM 149123101 4,607 36,471 SH   SOLE   0 0 36,471
CHEMOURS CO COM 163851108 10,846 725,976 SH   SOLE   0 0 725,976
CHEVRON CORP COM 166764100 6,891 58,102 SH   SOLE   0 0 58,102
CHURCH & DWIGHT CO INC COM 171340102 11,358 150,963 SH   SOLE   0 0 150,963
CISCO SYSTEMS INC COM 17275R102 7,051 142,707 SH   SOLE   0 0 142,707
COASTAL CARIBBEAN OILS & MINER COM 190432203 0 69,910 SH   SOLE   0 0 69,910
COCA-COLA COMPANY COM 191216100 2,280 41,882 SH   SOLE   0 0 41,882
COLGATE-PALMOLIVE COMPANY COM 194162103 460 6,252 SH   SOLE   0 0 6,252
COMCAST CORP NEW CL A COM 20030N101 434 9,632 SH   SOLE   0 0 9,632
CONOCOPHILLIPS COM 20825C104 315 5,534 SH   SOLE   0 0 5,534
CORNING INC. COM 219350105 693 24,300 SH   SOLE   0 0 24,300
CORTEVA INC COM 22052L104 30,970 1,106,079 SH   SOLE   0 0 1,106,079
CVS CAREMARK CORPORATION COM 126650100 508 8,050 SH   SOLE   0 0 8,050
DANAHER CORP COM 235851102 610 4,225 SH   SOLE   0 0 4,225
DEERE AND CO. COM 244199105 211 1,250 SH   SOLE   0 0 1,250
DENTSPLY SIRONA INC COM 24906P109 2,220 41,650 SH   SOLE   0 0 41,650
DISCOVER FINANCIAL SERVICES COM 254709108 478 5,892 SH   SOLE   0 0 5,892
DOMINION RESOURCES INC OF VA COM 25746U109 4,519 55,757 SH   SOLE   0 0 55,757
DOVER CORPORATION COM 260003108 227 2,285 SH   SOLE   0 0 2,285
DOW CHEMICAL COMPANY (THE) COM 260543103 52,644 1,104,798 SH   SOLE   0 0 1,104,798
DTE ENERGY COM 233331107 400 3,011 SH   SOLE   0 0 3,011
DU PONT (E.I.) DE NEMOURS & CO COM 263534109 78,790 1,104,897 SH   SOLE   0 0 1,104,897
DUKE ENERGY CORP COM 26441C204 1,599 16,677 SH   SOLE   0 0 16,677
ELI LILLY & CO COM 532457108 540 4,833 SH   SOLE   0 0 4,833
EMERSON ELECTRIC CO. COM 291011104 950 14,206 SH   SOLE   0 0 14,206
ENBRIDGE INC. COM 29250N105 937 26,714 SH   SOLE   0 0 26,714
EXELON CORP COM 30161N101 238 4,936 SH   SOLE   0 0 4,936
EXXON MOBIL CORPORATION COM 30231G102 10,692 151,420 SH   SOLE   0 0 151,420
FEDERAL REALTY INV TR S B I COM 313747206 1,549 11,374 SH   SOLE   0 0 11,374
FEDEX CORP COM 31428X106 4,463 30,658 SH   SOLE   0 0 30,658
FISERV INC COM 337738108 320 3,090 SH   SOLE   0 0 3,090
FORTIVE CORP COM 34959J108 308 4,488 SH   SOLE   0 0 4,488
FRANKLIN RESOURCES INC COM 354613101 652 22,585 SH   SOLE   0 0 22,585
GENERAL ELECTRIC COMPANY COM 369604103 1,893 211,703 SH   SOLE   0 0 211,703
GENERAL MILLS INC COM 370334104 750 13,614 SH   SOLE   0 0 13,614
GRAHAM HOLDINGS CO. COM 384637104 232 349 SH   SOLE   0 0 349
HEALTH CARE PPTY INVS COM 40414L109 268 7,524 SH   SOLE   0 0 7,524
HERSHEY COMPANY COM 427866108 1,827 11,787 SH   SOLE   0 0 11,787
HOME DEPOT COM 437076102 1,135 4,891 SH   SOLE   0 0 4,891
HONEYWELL INTERNATIONAL INC COM 438516106 2,885 17,052 SH   SOLE   0 0 17,052
ILLINOIS TOOL WORKS INC. COM 452308109 10,222 65,324 SH   SOLE   0 0 65,324
INTEL CORP COM COM 458140100 6,706 130,134 SH   SOLE   0 0 130,134
INTERNATIONAL BUSINESS MACHINE COM 459200101 3,141 21,602 SH   SOLE   0 0 21,602
INTERNATIONAL PAPER CO COM 460146103 239 5,709 SH   SOLE   0 0 5,709
INTUIT INC COM 461202103 957 3,600 SH   SOLE   0 0 3,600
ISHARES MSCI EAFE INDEX COM 464287465 364 5,584 SH   SOLE   0 0 5,584
ISHARES NASDAQ BIOTECH INDEX COM 464287556 5,428 54,551 SH   SOLE   0 0 54,551
ISHARES RUSSELL 2000 IDX COM 464287655 4,655 30,762 SH   SOLE   0 0 30,762
ISHARES RUSSELL MIDCAP INDEX COM 464287499 6,673 119,273 SH   SOLE   0 0 119,273
JOHNSON & JOHNSON COM 478160104 14,091 108,908 SH   SOLE   0 0 108,908
JPMORGAN CHASE & CO. COM 46625H100 11,225 95,379 SH   SOLE   0 0 95,379
KELLOGG COMPANY COM 487836108 2,648 41,146 SH   SOLE   0 0 41,146
KEYCORP COM 493267108 225 12,600 SH   SOLE   0 0 12,600
KIMBERLY-CLARK CORP COM 494368103 2,931 20,633 SH   SOLE   0 0 20,633
LABORATORY CORP OF AMERICA COM 50540R409 1,033 6,147 SH   SOLE   0 0 6,147
LINDE PLC COM G5494J103 369 1,907 SH   SOLE   0 0 1,907
LOCKHEED MARTIN COM 539830109 941 2,412 SH   SOLE   0 0 2,412
LOWES COS COM 548661107 11,731 106,681 SH   SOLE   0 0 106,681
M & T BANK CORP COM 55261F104 2,140 13,550 SH   SOLE   0 0 13,550
MANPOWER INC WISCONSIN COM 56418H100 398 4,724 SH   SOLE   0 0 4,724
MARRIOTT INTERNATIONAL, NEW IN COM 571903202 6,804 54,706 SH   SOLE   0 0 54,706
MC DONALD'S CORPORATION COM 580135101 12,385 57,684 SH   SOLE   0 0 57,684
MEDTRONIC INC COM G5960L103 483 4,442 SH   SOLE   0 0 4,442
MERCK & COMPANY INCORPORATED N COM 58933Y105 6,328 75,178 SH   SOLE   0 0 75,178
MICROSOFT CORPORATION COM 594918104 17,577 126,425 SH   SOLE   0 0 126,425
MONDELEZ INTL INC COM 609207105 265 4,797 SH   SOLE   0 0 4,797
MORGAN STANLEY & CO COM 617446448 516 12,088 SH   SOLE   0 0 12,088
MOTOROLA SOLUTIONS, INC COM 620076307 883 5,184 SH   SOLE   0 0 5,184
NESTLE SA REG ADR COM 641069406 250 2,303 SH   SOLE   0 0 2,303
NEXTERA ENERGY COM 65339F101 5,268 22,608 SH   SOLE   0 0 22,608
NORFOLK SOUTHERN CORP COM 655844108 275 1,531 SH   SOLE   0 0 1,531
NORTHERN TRUST CORP COM 665859104 971 10,400 SH   SOLE   0 0 10,400
ORACLE CORP COM 68389X105 437 7,949 SH   SOLE   0 0 7,949
PEPSICO INCORPORATED COM 713448108 12,751 93,004 SH   SOLE   0 0 93,004
PFIZER INCORPORATED COM 717081103 1,348 37,522 SH   SOLE   0 0 37,522
PHILIP MORRIS INTERNATIONAL COM 718172109 377 4,968 SH   SOLE   0 0 4,968
PHILLIPS 66 COM 718546104 475 4,638 SH   SOLE   0 0 4,638
PNC FINANCIAL SERVICES GROUP COM 693475105 513 3,659 SH   SOLE   0 0 3,659
POWERSHARES QQQ TR ETF SERIES COM 73935A104 1,173 6,211 SH   SOLE   0 0 6,211
PROCTER & GAMBLE COMPANY COM 742718109 16,306 131,099 SH   SOLE   0 0 131,099
PUBLIC SERVICE ENTERPRISE GROU COM 744573106 281 4,525 SH   SOLE   0 0 4,525
RAYTHEON COMPANY NEW COM 755111507 216 1,100 SH   SOLE   0 0 1,100
SAUL CENTERS INC. COM 804395101 380 6,978 SH   SOLE   0 0 6,978
SELECT SECTOR SPDR TR UTILITIE COM 81369Y886 291 4,500 SH   SOLE   0 0 4,500
SMUCKER J.M. CO COM 832696405 551 5,006 SH   SOLE   0 0 5,006
SOUTHERN COMPANY (THE) COM 842587107 3,242 52,487 SH   SOLE   0 0 52,487
SPDR S&P 500 ETF COM 78462F103 335 1,128 SH   SOLE   0 0 1,128
SYSCO CORPORATION COM 871829107 1,387 17,467 SH   SOLE   0 0 17,467
T ROWE PRICE GROUP INC. COM 74144T108 11,463 100,329 SH   SOLE   0 0 100,329
TARGET CORP COM 87612E106 615 5,756 SH   SOLE   0 0 5,756
TEXAS INSTRUMENTS COM 882508104 846 6,548 SH   SOLE   0 0 6,548
THE TJX COMPANIES COM 872540109 223 4,000 SH   SOLE   0 0 4,000
THE TRAVELERS COS INC COM 89417E109 614 4,127 SH   SOLE   0 0 4,127
THERMO FISHER SCIENTIFIC COM 883556102 465 1,595 SH   SOLE   0 0 1,595
UDR INC COM 902653104 996 20,549 SH   SOLE   0 0 20,549
UNILEVER COM 904784709 288 4,800 SH   SOLE   0 0 4,800
UNION PACIFIC CORP COM 907818108 5,958 36,783 SH   SOLE   0 0 36,783
UNITED HEALTHCARE CORP COM 91324P102 5,296 24,368 SH   SOLE   0 0 24,368
UNITED TECHNOLOGIES CORP COM COM 913017109 8,017 58,723 SH   SOLE   0 0 58,723
US BANCORP DEL (NEW) COM 902973304 254 4,585 SH   SOLE   0 0 4,585
VANGUARD EMERGING MARKETS ETF COM 922042858 722 17,924 SH   SOLE   0 0 17,924
VANGUARD FTSE DEVELOPED MARKET COM 921943858 1,138 27,699 SH   SOLE   0 0 27,699
VANGUARD INFORMATION TECHNOLOG COM 92204A702 45,359 210,434 SH   SOLE   0 0 210,434
VANGUARD MID CAP ETF COM 922908629 5,812 34,679 SH   SOLE   0 0 34,679
VANGUARD REIT ETF COM 922908553 663 7,110 SH   SOLE   0 0 7,110
VANGUARD S&P ETF COM 922908363 913 3,350 SH   SOLE   0 0 3,350
VANGUARD SMALL CAP ETF COM 922908751 4,256 27,658 SH   SOLE   0 0 27,658
VANGUARD TOTAL STOCK MARKET COM 922908769 2,760 18,280 SH   SOLE   0 0 18,280
VERIZON COMMUNICATIONS COM 92343V104 4,380 72,563 SH   SOLE   0 0 72,563
VISA INC CLASS A COM 92826C839 11,217 65,211 SH   SOLE   0 0 65,211
VULCAN MATERIALS CO COM 929160109 363 2,400 SH   SOLE   0 0 2,400
WAL-MART STORES INC COM 931142103 414 3,492 SH   SOLE   0 0 3,492
WALGREENS BOOTS ALLIANCE, INC. COM 931427108 4,209 76,100 SH   SOLE   0 0 76,100
WALT DISNEY COMPANY COM 254687106 8,333 63,942 SH   SOLE   0 0 63,942
WASH REAL ESTATE INV TRUST S B COM 939653101 2,341 85,555 SH   SOLE   0 0 85,555
WASTE CONNECTIONS INC COM 94106B101 350 3,800 SH   SOLE   0 0 3,800
WEINGARTEN REALTY INVS S B I COM 948741103 2,283 78,382 SH   SOLE   0 0 78,382
WELLS FARGO & CO. NEW COM 949746101 5,615 111,316 SH   SOLE   0 0 111,316
WEYERHAEUSER CO COM 962166104 292 10,539 SH   SOLE   0 0 10,539
WHITE MOUNTAINS INS. COM G9618E107 215 199 SH   SOLE   0 0 199
YUM BRANDS INC COM 988498101 226 1,995 SH   SOLE   0 0 1,995
ZIMMER BIOMET HOLDINGS INC. COM 98956P102 458 3,340 SH   SOLE   0 0 3,340