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
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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 1,350 6,861 SH   SOLE NONE 0 0 6,861
Abbott Labs COM 002824100 1,369 22,453 SH   SOLE NONE 0 0 22,453
Abbvie Inc COM 00287Y109 1,439 15,530 SH   SOLE NONE 0 0 15,530
Align Technology, Inc. COM 016255101 3,711 10,845 SH   SOLE NONE 4,110 0 6,735
Alphabet Cl A CAP STK CL A 02079K305 2,745 2,431 SH   SOLE NONE 365 0 2,066
Alphabet Cl C CAP STK CL C 02079K107 3,084 2,764 SH   SOLE NONE 1,039 0 1,725
Altria Group Inc COM 02209S103 1,065 18,751 SH   SOLE NONE 0 0 18,751
Amazon.Com COM 023135106 4,601 2,707 SH   SOLE NONE 995 0 1,712
American Tower Corp COM 03027X100 4,793 33,246 SH   SOLE NONE 9,013 0 24,233
American Water Works COM 030420103 2,665 31,215 SH   SOLE NONE 8,470 0 22,745
Ametek Inc COM 031100100 2,486 34,445 SH   SOLE NONE 13,125 0 21,320
Amgen Inc COM 031162100 727 3,939 SH   SOLE NONE 0 0 3,939
Apple Computer Inc COM 037833100 2,441 13,189 SH   SOLE NONE 238 0 12,951
At&t Corp Com New COM 00206R102 468 14,576 SH   SOLE NONE 0 0 14,576
Bank Of Amer Corp COM 060505104 123 4,365 SH   SOLE NONE 0 0 4,365
Berkshire Hathaway Class A CL A 084670108 282 1 SH   SOLE NONE 0 0 1
Berkshire Hathaway Class B New CL B NEW 084670702 932 4,994 SH   SOLE NONE 0 0 4,994
Blackrock Inc. COM 09247X101 3,732 7,478 SH   SOLE NONE 2,720 0 4,758
Blackstone Group LP COM UNIT LTD 09253U108 269 8,371 SH   SOLE NONE 1,449 0 6,922
Booking Hldgs Inc COM 09857L108 2,595 1,280 SH   SOLE NONE 369 0 911
Bright Horizons Family COM 109194100 1,082 10,550 SH   SOLE NONE 3,940 0 6,610
Bristol Myers Squibb Co COM 110122108 409 7,383 SH   SOLE NONE 0 0 7,383
CME Group COM CL A 12572Q105 4,309 26,289 SH   SOLE NONE 9,539 0 16,750
Chevron Texaco Corp COM 166764100 434 3,436 SH   SOLE NONE 0 0 3,436
Cisco Systems Inc COM 17275R102 269 6,249 SH   SOLE NONE 2,496 0 3,753
Coca Cola Co COM 191216100 211 4,810 SH   SOLE NONE 987 0 3,823
Comcast Corp New Cl A CL A 20030N101 295 9,006 SH   SOLE NONE 0 0 9,006
Concho Resources Inc COM 20605P101 2,180 15,759 SH   SOLE NONE 5,473 0 10,286
Danaher Corp COM 235851102 4,028 40,821 SH   SOLE NONE 12,891 0 27,930
Disney Walt Co Holding Co COM DISNEY 254687106 331 3,157 SH   SOLE NONE 0 0 3,157
Dover Corp COM 260003108 1,909 26,080 SH   SOLE NONE 8,460 0 17,620
Ecolab Inc. COM 278865100 3,214 22,903 SH   SOLE NONE 7,399 0 15,504
Emerson Electric Co COM 291011104 338 4,892 SH   SOLE NONE 0 0 4,892
Equinix Inc COM PAR $0.001 29444U700 2,126 4,945 SH   SOLE NONE 1,640 0 3,305
Exxon Mobil Corp COM 30231G102 1,434 17,337 SH   SOLE NONE 1,200 0 16,137
Facebook CL A 30303M102 4,162 21,420 SH   SOLE NONE 6,154 0 15,266
First Republic Bank San Franci COM 33616C100 4,268 44,099 SH   SOLE NONE 14,320 0 29,779
Fiserv Inc Wis COM 337738108 2,330 31,454 SH   SOLE NONE 11,622 0 19,832
General Mills COM 370334104 237 5,363 SH   SOLE NONE 0 0 5,363
Genuine Parts Co COM 372460105 354 3,854 SH   SOLE NONE 0 0 3,854
Goldman Sachs Group Inc COM 38141G104 161 728 SH   SOLE NONE 150 0 578
Halliburton Co COM 406216101 97 2,156 SH   SOLE NONE 0 0 2,156
Home Depot Inc COM 437076102 1,656 8,486 SH   SOLE NONE 0 0 8,486
Idexx Laboratories Inc COM 45168D104 3,371 15,469 SH   SOLE NONE 5,425 0 10,044
Illumina Inc COM 452327109 3,220 11,529 SH   SOLE NONE 4,369 0 7,160
Intel Corp COM 458140100 260 5,240 SH   SOLE NONE 0 0 5,240
Intl Business Mach COM 459200101 210 1,500 SH   SOLE NONE 0 0 1,500
JP Morgan Chase COM 46625H100 8,348 80,110 SH   SOLE NONE 10,554 0 69,556
Johnson & Johnson Com COM 478160104 2,921 24,070 SH   SOLE NONE 7,785 0 16,285
Markel COM 570535104 2,033 1,875 SH   SOLE NONE 561 0 1,314
Massimo Corporation COM 574795100 1,201 12,295 SH   SOLE NONE 4,200 0 8,095
Mastercard Inc. CL A 57636Q104 6,574 33,451 SH   SOLE NONE 9,520 0 23,931
Medtronic Inc SHS G5960L103 378 4,417 SH   SOLE NONE 0 0 4,417
Merck & Co Inc New Com COM 58933Y105 816 13,440 SH   SOLE NONE 0 0 13,440
Microsoft Corp Com COM 594918104 1,619 16,419 SH   SOLE NONE 3,312 0 13,107
Morgan Stanley COM NEW 617446448 63 1,320 SH   SOLE NONE 0 0 1,320
Netflix, Inc COM 64110L106 3,585 9,159 SH   SOLE NONE 3,470 0 5,689
Nike Inc CL B 654106103 536 6,730 SH   SOLE NONE 0 0 6,730
Novartis Ag Spon Adr SPONSORED ADR 66987V109 177 2,339 SH   SOLE NONE 0 0 2,339
Pepsico Inc COM 713448108 331 3,037 SH   SOLE NONE 0 0 3,037
Pfizer Inc Com COM 717081103 760 20,950 SH   SOLE NONE 890 0 20,060
Philip Morris International COM 718172109 1,116 13,817 SH   SOLE NONE 444 0 13,373
Pnc Financial Services Group I COM 693475105 260 1,928 SH   SOLE NONE 0 0 1,928
Price T Rowe Group Inc. COM 74144T108 506 4,356 SH   SOLE NONE 0 0 4,356
Procter & Gamble Co COM 742718109 1,278 16,374 SH   SOLE NONE 827 0 15,547
Roper Technologies COM 776696106 4,691 17,003 SH   SOLE NONE 5,479 0 11,524
Royal Dutch Shell Class A SPONS ADR A 780259206 2,048 29,582 SH   SOLE NONE 0 0 29,582
Target Corp COM 87612E106 365 4,790 SH   SOLE NONE 0 0 4,790
Teleflex Incorporated COM 879369106 1,860 6,935 SH   SOLE NONE 2,610 0 4,325
Teradyne COM 880770102 1,574 41,350 SH   SOLE NONE 16,375 0 24,975
Unilever Plc SPON ADR NEW 904767704 487 8,814 SH   SOLE NONE 0 0 8,814
United Technologies Corp COM 913017109 388 3,100 SH   SOLE NONE 0 0 3,100
V. F. Corporation COM 918204108 848 10,407 SH   SOLE NONE 40 0 10,367
Verizon Communications COM 92343V104 621 12,347 SH   SOLE NONE 0 0 12,347
Visa Inc. COM CL A 92826C839 3,013 22,748 SH   SOLE NONE 5,327 0 17,421
Wells Fargo & Co New COM 949746101 140 2,523 SH   SOLE NONE 0 0 2,523
West Pharmaceuticals Services COM 955306105 2,103 21,179 SH   SOLE NONE 6,195 0 14,984
Worldpay Inc. CL A 981558109 2,023 24,741 SH   SOLE NONE 9,441 0 15,300
XYLEM Inc. COM 98419M100 1,192 17,685 SH   SOLE NONE 6,220 0 11,465
Zayo Group Holdings Inc. COM 98919V105 1,900 52,075 SH   SOLE NONE 17,500 0 34,575
Zoetis Inc. CL A 98978V103 2,245 26,355 SH   SOLE NONE 9,300 0 17,055