60 



ERIE CLIFF. 

 Plate XXV. 



This section is best approached from Hamburgh-on-the- 

 lake station. To the right of the road which leads from the 

 station to the shore, is Avery's Creek,* a small stream, 

 which has cut several sections in the rock. Near the rail- 

 road crossing, the hard layer, six feet above the Trilobite 

 beds, appears in the bank, included by shale above and 

 below. Farther down the stream, the Trilobite layers are 

 exposed in the bed of the stream, where they are the cause of 

 rapids. They contain essentially the same fauna as at 

 Eighteen Mile Creek and the sections on the Lake Shore, 

 except that the trilobites are somewhat less abundant. The 

 beds here are subdivided as follows in descending order : 



Argillo-arenaceous limestone 3 inches 



Shale with few fossils 3 



Limestone similar to above 4- " 



Fissile shale 8 " 



Arenaceous limestone, somewhat shah' and very 

 fossiliferous 12 



(» 



Total 30 inches 



In the middle bed the rare trilobite Homalonotus dekayi 

 (Green) was found. The two feet of shale next below the 

 Trilobite beds contain a rich fauna, which recalls the fauna 

 of the Demissa bed in the upper Hamilton shales. Spirifer 

 mucronatus (Conrad) is very common, and Athvris spirifer- 

 oides (Eaton), and Streptelasma rectum Hall are likewise 

 abundant. Rhipidomella penelope Hall is one of the rarer 

 forms found here, Tropidolcptus carinatus ( Conrad ) being 

 another. Rhipidomella leucosia Hall and R. cvchis Hall 

 are among the forms seldom found above this shale. Alto- 

 gether more than thirty species of fossils occur, most of 

 which are brachiopods.f 



*The stream is named after Mr. Truman (",. Avery, the proprietor of the land 

 through which it runs. 



IFor a list of the fossils obtained from these and the lower beds see the author's 

 paper on the Faunas Of the Hamilton Group of Eighteen Mile Creek and vicinity. 

 —Ann. Rept. State Geol. X. V. 1*96. 



