238 



Report of the State Geologist. 



bed appears as a prominent band. About eight feet of shale lie above 

 it, but owing to the presence of much talus the Pleurodictyum beds are not 

 generally visible, though on climbing the bank the Nautilus bed can usually 

 be seen resting upon the Strophalosia bed. The presence of the Pleuro- 

 dictyum beds is, however, indicated by the abundance of P. stylopora 

 on the beach at the foot of the cliff. Specimens of Nautilus magister 

 are also occasionally found, while the rock of the Nautilus bed, filled with 

 Ambocmlia umbonata var. nana is of common occurrence. 



Avery* s creek. In the lower portion of the ravine of this stream the 

 transition beds are exposed ; the Strophalosia bed which terminates them also 

 appears in places, though talus more or less obscures it. Where the Lake Shore 

 road crosses the ravine, the Strophalosia bed appears in the bed of the stream, 

 causing a small fall. The banks of the ravine above the fall are low, seldom 

 rising more than five feet, but as the stream-bed rapidly rises, the successive 

 layers overlying the Strophalosia bed are exposed. This is the best locality 

 for collecting the fossils from the Pleurodictyum and Nautilus beds, 

 and the shales between the former and the Trilobite beds are well exposed. 

 The latter cause a series of rapids in the stream, half way between the lake 

 shore and the railroad track, near which the upper hard layer is exposed. 



Wanalali cliff. This cliff begins less than a mile and a half south of 

 the termination of Erie cliff, the shore between the two being low, and more 

 01 less drift covered. The cliff soon rises to a height of about seventy «five feet, 

 exposing in succession the Lower shales, from the Trilobite beds upwards, the 

 Encrinal limestone, the Moscow shales, and the grey and black Genesee shales. 

 The cliff in many places is almost perpendicular, and presents one of the finest 

 sections to be found in this vicinity. At the base are the Trilobite beds which 

 form a prominent bench for some distance along the shore. Owing to the 

 direction of the section which swings around to the west, the Trilobite beds 

 appear higher up in the bank as we go southward, the cliff at the same time 

 becoming lower. The upper calcareous bed appears prominently in the cliff, 

 being about half way up near the southern end. The Modiomorpha subalata 

 led also appears in fresh portions of the cliff, forming a narrow band. Its 

 characteristic fossils may be best obtained in a little ravine near the middle of 

 the section where the bed causes a small fall in the stream. At the lower 

 end of the section the Pleurodictyum beds appear on the beach, the fossils 

 being occasionally pyritized. Between this section and the next, is an old river 

 gorge about 1,000 feet wide, and filled with till containing many Corniferous 

 limestone boulders. 



