REPORT OF THE STATE PALEONTOLOGIST 1901 425 



on the geologic map of the state, and to establish a base mark 

 or guide for the plotting of the formations immediately above 

 and below, to trace the outcrops of the Tully limestone from 

 Owasco lake eastward into Madison county. Mr Luther was 

 engaged for a short time in the work of locating these outcrops 

 on the Tully and Cazenovia quadrangles. The Tully topo- 

 graphic sheet lies directly south of the Syracuse sheet and 

 covers a very interesting section of the rock series. It has 

 therefore seemed desirable to complete the areal work on this 

 sheet, and this will be finished before the close of the present 

 field season. The field work is in charge of Mr Luther. 



Contact lines of formations in the region about Tonawanda and 

 Oak Orchard creek swamps. The great swamp area lying east 

 and west along the course of the Tonawanda creek and its 

 branches and extending to the northeastward along the Oak 

 Orchard creek and its tributaries, covering a vast acreage in 

 the territory- between Churchville at the east and Buffalo at 

 the west, a distance of 75 miles, has naturally obscured the 

 rock geology of a very large area in western New York. The 

 question as to the direction and position of the actual contact 

 lines of formations on which this lowland rests came up during 

 the course of the season in the special consideration of a rela- 

 tively new member in our succession of faunas lying at the top 

 of the Niagara escarpment, the so called Guelph fauna of the 

 Rochester section, to which fuller reference will be presently 

 made. This depressed region, h ing largely between the escarp- 

 ments of the Lockport dolomites on the north and the Onondaga 

 limestone on the south, has not been the subject of extended 

 geologic investigation, and so far as my knowledge extends no 

 careful traverses of it for the end which has now been in view, 

 have been made since the early survey of 1836-13. The very 

 great scarcity of outcrops, the depth of the drift mantle, and 

 the generally unbroken and monotonous aspect of the country 

 from a geologic point of view, have rendered the attempt to 

 trace the formational contacts one of some difficulty. The 

 paleontologist, accompanied by Dr Euedemann and 1>. 1). 



