GAMACHIAN SERIES 701 



representative elsewhere in North America. These strata are seen to 

 best advantage at Gamache (or Ellis) Bay, where the characteristic fos- 

 sils of the series occur in abundance. On Anticosti it embraces all of the 

 Ellis Bay stage, but eventually it may possibly be shown that the upper 

 portion of the Charleton stage should be included in this series. In other 

 words, this Gamachian series is intended to include all American deposits 

 later in age than the youngest Eichmondian of Indiana and Ohio and 

 older than the Anticosti series, which in the United States is thought to 

 have its basal equivalent in the typical Medina and Edgewood stages. 



Ellis Bay formation (lower half of Richardson's Division 0). — The 

 various zones of this formation are best seen about Ellis Bay, at the 

 southwestern end of Anticosti Island. The lowest strata are met with 

 at Junction Cliff, the first prominent cliff to the east of West Point light- 

 house, and the higher beds appear in order to Cape Henry, the western 

 point of Ellis Bay. In this bay may be seen the zones from C5 to Cg. In 

 White Cliff and on the adjacent reef on the eastern side of Ellis Bay may 

 be studied the zones Cg and C7, and the succeeding strata come in as one 

 goes eastward to Bear Cliff, the eastern horn of the bay, where the divid- 

 ing line between C and D is laid at the top of Eichardson^s Cn- These 

 eleven zones of the Ellis Bay formation have a united thickness of 180 

 feet. They are the eleven lower divisions of C as defined by Eichardson ; 

 the remaining three higher zones of his C are here referred to Division D. 

 As will be pointed out, the fauna of these higher beds is clearly still 

 Eichmondian ; but a number of forms are introduced that continue into D 

 and are prophetic of the nearness of Siluric time. 



The Ellis Bay formation consists largely of thin-bedded gray limestone 

 with shale partings and distinct zones of shale, particularly in the lower 

 half, in which fine fossils abound. Toward the top the first well devel- 

 oped coral reefs are present — a faunal aspect that often dominates the 

 higher formation. 



The zones of Eichardson^s section, somewhat emended, are as follows: 

 Dinorthis porcata beds (second occurrence). p^^^ 



Cj to C4 or Junction Cliff beds. Lower 20 feet consist of blue sbale 

 with thin limestones. There is more shale here than in the 

 upper 40 feet, where the brittle and hard gray to bluish gray 

 limestones with thin shale partings become more prominent. . . 60 

 C5. Ash gray argillaceous limestone interbedded with shale. To be 



seen just east of Menier's wharf, Ellis Bay, in a small quarry . . 6 



ParastropMa reversa heds. 



Cg. Ash gray argillaceous limestones and shales 20 



C7 to Cs. Ash gray argillaceous limestone with little shale. Below, 

 the beds are of the ash gray color, but at the top they are 

 darker and thinner-bedded. Seen in White Cliff, Ellis Bay... 62 



