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 1,226 7,016 SH   SOLE NONE 0 0 7,016
AES Corp COM 00130H105 251 10,700 SH   SOLE NONE 0 0 10,700
Abbott Labs COM 002824100 2,447 22,346 SH   SOLE NONE 0 0 22,346
Abbvie Inc COM 00287Y109 1,744 16,272 SH   SOLE NONE 0 0 16,272
Alphabet Cl A CAP STK CL A 02079K305 4,727 2,697 SH   SOLE NONE 365 0 2,332
Alphabet Cl C CAP STK CL C 02079K107 5,412 3,089 SH   SOLE NONE 1,019 0 2,070
Altria Group Inc COM 02209S103 485 11,819 SH   SOLE NONE 0 0 11,819
Amazon.Com COM 023135106 8,634 2,651 SH   SOLE NONE 713 0 1,938
American Tower Corp COM 03027X100 4,844 21,580 SH   SOLE NONE 6,910 0 14,670
American Water Works COM 030420103 4,498 29,311 SH   SOLE NONE 8,296 0 21,015
Ametek Inc COM 031100100 3,666 30,315 SH   SOLE NONE 12,735 0 17,580
Amgen Inc COM 031162100 797 3,465 SH   SOLE NONE 0 0 3,465
Apple Computer Inc COM 037833100 18,297 137,890 SH   SOLE NONE 16,393 0 121,497
At&t Corp Com New COM 00206R102 149 5,196 SH   SOLE NONE 0 0 5,196
Bank Of Amer Corp COM 060505104 269 8,859 SH   SOLE NONE 0 0 8,859
Berkshire Hathaway Class A CL A 084670108 348 1 SH   SOLE NONE 0 0 1
Berkshire Hathaway Class B New CL B NEW 084670702 2,737 11,803 SH   SOLE NONE 1,235 0 10,568
Blackrock Inc. COM 09247X101 6,954 9,638 SH   SOLE NONE 2,725 0 6,913
Booking Hldgs Inc COM 09857L108 334 150 SH   SOLE NONE 0 0 150
Bright Horizons Family COM 109194100 3,333 19,265 SH   SOLE NONE 5,300 0 13,965
Bristol Myers Squibb Co COM 110122108 325 5,241 SH   SOLE NONE 0 0 5,241
CME Group COM 12572Q105 4,644 25,510 SH   SOLE NONE 8,001 0 17,509
Chevron Texaco Corp COM 166764100 117 1,388 SH   SOLE NONE 0 0 1,388
Cisco Systems Inc COM 17275R102 496 11,094 SH   SOLE NONE 2,496 0 8,598
Coca Cola Co COM 191216100 254 4,631 SH   SOLE NONE 987 0 3,644
Copart Inc. COM 217204106 2,907 22,843 SH   SOLE NONE 6,550 0 16,293
Danaher Corp COM 235851102 8,360 37,633 SH   SOLE NONE 10,770 0 26,863
Disney Walt Co Holding Co COM 254687106 451 2,491 SH   SOLE NONE 0 0 2,491
Dover Corp COM 260003108 4,210 33,346 SH   SOLE NONE 8,896 0 24,450
Ecolab Inc. COM 278865100 4,539 20,977 SH   SOLE NONE 7,153 0 13,824
Emerson Electric Co COM 291011104 46 570 SH   SOLE NONE 0 0 570
Equinix Inc COM 29444U700 3,717 5,205 SH   SOLE NONE 1,695 0 3,510
Exxon Mobil Corp COM 30231G102 424 10,284 SH   SOLE NONE 0 0 10,284
Facebook CL A 30303M102 793 2,902 SH   SOLE NONE 304 0 2,598
Fair Isaac Corp. COM 303250104 4,128 8,077 SH   SOLE NONE 2,225 0 5,852
First Republic Bank San Franci COM 33616C100 1,880 12,798 SH   SOLE NONE 355 0 12,443
Fiserv Inc Wis COM 337738108 4,065 35,706 SH   SOLE NONE 10,967 0 24,739
Genuine Parts Co COM 372460105 387 3,854 SH   SOLE NONE 0 0 3,854
Goldman Sachs Group Inc COM 38141G104 325 1,233 SH   SOLE NONE 35 0 1,198
Heico Corp. COM 422806109 2,635 19,901 SH   SOLE NONE 6,635 0 13,266
Home Depot Inc COM 437076102 2,003 7,541 SH   SOLE NONE 0 0 7,541
Honeywell Inc COM 438516106 332 1,563 SH   SOLE NONE 0 0 1,563
Idexx Laboratories Inc COM 45168D104 6,151 12,306 SH   SOLE NONE 4,625 0 7,681
Illumina Inc COM 452327109 4,119 11,132 SH   SOLE NONE 4,040 0 7,092
Intel Corp COM 458140100 593 11,901 SH   SOLE NONE 0 0 11,901
JP Morgan Chase COM 46625H100 10,493 82,578 SH   SOLE NONE 10,348 0 72,230
Johnson & Johnson Com COM 478160104 3,403 21,622 SH   SOLE NONE 7,785 0 13,837
MSCI COM 55354G100 3,655 8,185 SH   SOLE NONE 2,080 0 6,105
Markel COM 570535104 2,783 2,693 SH   SOLE NONE 637 0 2,056
Marketaxess Holdings COM 57060D108 2,651 4,646 SH   SOLE NONE 1,455 0 3,191
Massimo Corporation COM 574795100 3,582 13,346 SH   SOLE NONE 4,150 0 9,196
Mastercard Inc. CL A 57636Q104 10,782 30,207 SH   SOLE NONE 6,635 0 23,572
Medtronic Inc SHS G5960L103 489 4,176 SH   SOLE NONE 0 0 4,176
Merck & Co Inc New Com COM 58933Y105 1,060 12,955 SH   SOLE NONE 0 0 12,955
Microsoft Corp Com COM 594918104 5,629 25,310 SH   SOLE NONE 3,499 0 21,811
Morgan Stanley COM NEW 617446448 242 3,531 SH   SOLE NONE 0 0 3,531
Netflix, Inc COM 64110L106 4,982 9,214 SH   SOLE NONE 3,320 0 5,894
Nike Inc CL B 654106103 980 6,930 SH   SOLE NONE 0 0 6,930
Novartis Ag Spon Adr SPONSORED ADR 66987V109 388 4,114 SH   SOLE NONE 0 0 4,114
Paycom Software Inc COM 70432V102 5,204 11,506 SH   SOLE NONE 2,610 0 8,896
Paypal Holdings Inc COM 70450Y103 419 1,790 SH   SOLE NONE 0 0 1,790
Pepsico Inc COM 713448108 264 1,781 SH   SOLE NONE 0 0 1,781
Pfizer Inc Com COM 717081103 1,062 28,838 SH   SOLE NONE 890 0 27,948
Philip Morris International COM 718172109 725 8,758 SH   SOLE NONE 0 0 8,758
Price T Rowe Group Inc. COM 74144T108 256 1,690 SH   SOLE NONE 0 0 1,690
Procter & Gamble Co COM 742718109 2,234 16,059 SH   SOLE NONE 827 0 15,232
Roper Technologies COM 776696106 7,338 17,021 SH   SOLE NONE 5,034 0 11,987
Royal Dutch Shell Class A SPONS ADR A 780259206 1,040 29,582 SH   SOLE NONE 0 0 29,582
SBA Communications Corp. CL A 78410G104 284 1,005 SH   SOLE NONE 15 0 990
Steris Plc SHS USD G8473T100 2,321 12,243 SH   SOLE NONE 3,155 0 9,088
Target Corp COM 87612E106 1,518 8,601 SH   SOLE NONE 0 0 8,601
Teladoc Health Inc. COM 87918A105 3,072 15,365 SH   SOLE NONE 5,475 0 9,890
Teledyne Inc COM 879360105 2,081 5,310 SH   SOLE NONE 1,310 0 4,000
Teleflex Incorporated COM 879369106 3,065 7,448 SH   SOLE NONE 2,585 0 4,863
Teradyne COM 880770102 3,560 29,696 SH   SOLE NONE 14,570 0 15,126
Trade Web Markets, Inc. CL A 892672106 1,612 25,817 SH   SOLE NONE 9,001 0 16,816
Tyler Technologies Inc COM 902252105 5,044 11,555 SH   SOLE NONE 2,535 0 9,020
Unilever Plc SPON ADR NEW 904767704 156 2,585 SH   SOLE NONE 0 0 2,585
Union Pacific Corp COM 907818108 213 1,025 SH   SOLE NONE 0 0 1,025
V. F. Corporation COM 918204108 544 6,367 SH   SOLE NONE 0 0 6,367
Veeva Systems, Inc. CL A COM 922475108 1,655 6,078 SH   SOLE NONE 1,845 0 4,233
Verizon Communications COM 92343V104 610 10,385 SH   SOLE NONE 0 0 10,385
Visa Inc. COM CL A 92826C839 3,872 17,704 SH   SOLE NONE 4,132 0 13,572
West Pharmaceuticals Services COM 955306105 5,578 19,690 SH   SOLE NONE 5,695 0 13,995
Zoetis Inc. CL A 98978V103 4,891 29,556 SH   SOLE NONE 8,586 0 20,970
Adams Diversified Equity COM 006212104 431 24,921 SH   SOLE NONE 0 0 24,921