April 13, 1883.] 



SCIENCE. 



269 



survey. The secondaiy stations along the 

 Mohawk valley are from four to seven miles 

 apart. Where tertiarj' work has been done, 

 the stations are from half a mile to a mile 

 distant from each other. 



In the matter of marking stations, the New 

 York survej' has dejiarted widelj- from the 

 method of the U. S. coast sm-vey, which has 

 preserved its points by burj-ing in the ground 

 within eighteen inches of the surface a pot, jug, 

 or other object, leaving no surface mark what- 

 ever. The state-survej' stations are marked 

 b}' sinking a hole five feet deep, in the bottom 

 of which is placed an earthen pot of truncated- 

 cone shape, with centre mark, and stamped 

 with the letters ' N. Y. S. S.' The earth is 

 rammed about and above this for about four 

 inches. A granite monument sis inches square 

 by four feet long is then placed in the hole, 

 and its centre adjusted over the pot. The 

 upper extremity of the stone, which projects 

 above ground, is di'essed, and the same letters 

 and the number which designates the station 

 are cut deeph" into it. Diagonal grooves on 

 the top of the stone mark its centre. 



The monuments are of one pattern, and 

 from a single quarrj-. These stones, deepty 

 embedded in the earth, are verj- difficult to 

 move or destroj^ without the perpetrator of 

 such an act being detected. Thej- are easilj- 

 found hj local survej'ors or others wishing to 

 identifj- the points. The action of freezing 

 and thawing unequall3- on the north and south 

 sides of the stones will eventually throw them 

 over toward the south. Any disturbance of 

 this kind can be detected hy the edges being- 

 out of plumb ; and the stone can be recentred 

 over the pot, which, being below frost-line, can 

 never move. In addition to the deeplj' buried 

 pot and stone, two witness-pots are buried 

 from twelve to eighteen inches deep, and three 

 feet from the station. On their tops are 

 stamped arrows which point to the station. 



The work of the survej' is carried on hy a 

 director and a permanent corps of ti'aiued as- 

 sistants divided into three parties, — two for 

 observing angles of the primary- and secondarj' 

 triangles, and one for sigiial-buildiug. Assist- 



ant O. S. Wilson, formerly of the U. S. noi'th- 

 west boundary survej', and Assistant Horace 

 Andrews, jun., formerly of the U. S. coast 

 survej', have charge of the observing parties ; 

 and Assistant O. H. Bogardus, of the signal- 

 building part}-. In addition to the regular 

 force, from six to nine heliotropers are em- 

 plo3-ed in summer. During the winters the 

 assistants are engaged in reducing the results, 

 and the preparation of maps and reports, in 

 the offices of the survey in the state capitol at 

 Albany. 



In the bill providing for the expenses of the 

 state government, an annual appropriation of 

 $15,800 is now made to carry on the survey. 



This sketch of the causes which brought 

 about the New York state survey, the purposes 

 for which it was instituted, its guiding policy-, 

 its plans, grade of precision, methods, and 

 organization, is essential to a right under- 

 standing of the results of the work whose 

 progress will be described hereafter. 



GLACIAL PHENOMENA IN OHIO. 



Prof. G. F. Wkight of Oberlin read a paper 

 before the Boston society of natural history 

 on the 7th of March, giving the results of his 

 work last summer in determining the exact 

 southern boundary or terminal moraine of the 

 glaciated area of Ohio. The course of this 

 boundary-line is shown upon the accompany- 

 ing map, and is a continuation of that traced 

 by him and Professor Lewis the previous year 

 across Pennsylvania. 



The terminal moraine in Ohio is not every- 

 where so prominent in its features as it is 

 south of New England, through Cape Cod, the 

 Elizabeth Islands, and Long Island ; but the 

 southern boundary of the glaciated region is 

 everywhere verj' sharply defined, and the 

 limits of the ice can be traced with nearlj' as 

 much certainty as the shores of the ocean. At 

 various places in Stark, Holmes, Fairfield, and 

 Ross counties there are vast piles of glaciated 

 material at the very limit of the glaciated re- 

 gion. All that portion of Ohio north and west 

 of the line above described is covered with the 

 material which was ground up underneath, and 

 transported by the moving ice. This consists 

 of unstratified fine clay, containing scratched 

 stones and fragments of rock of various kinds 

 from the north. The average depth of this 



