13 
extends along the south side for about 100 miles with an inter- 
ruption of about 30 miles where the Chicotte formation makes 
the shore. The eastern and western limits are somewhat differ- 
ent. In the basal zones of the western exposures is a zone from 
which the writer collected several hundred T riplecia insularis 
anticostiensis . The species has. not been seen in the eastern 
exposures. In the eastern exposures an extensive coral reef 
succeeded by limestone occurs near the base. Such does not 
occur on the west where a 60-foot zone of sandy almost un- 
fossiliferous shale, succeeded by 200 feet of highly calcareous 
shale — a marlite — filled with fossils, holds the interval in which 
the coral zone occurs on the east. In the calcareous shale and 
some of the limestone just above, Lissatrypa atheroidea, Onco- 
cer as futile, and Calymene n. sp. occur in considerable abundance. 
Not one of these has been seen to the east. Camarotoechia 
decemplicata is extremely abundant in the eastern exposures;’ 
it is rare in the west. At Belle river and the mouth of Pavilion 
river Orthis fiabellites is extremely common in the top zones of 
the Jupiter River. At the Jumpers where the same zones are 
exposed it is rare. 
The Chicotte formation consists of coral reef limestone 
without bedding and inter-reef deposits of well-bedded crystal- 
line and crinoidal limestone. In this formation one observes 
what the writer has previously pointed out for the Gotland 
sequence 1 — the organisms grew in colonies and the individuals 
vary with the colony, scouring occurred between the reefs and 
deposition in the quiet places and the bedding synclines from 
reef to reef. The deposits vary from place to place. At one 
place they are wholly crinoidal fragments, at another all brachio- 
pods, at another all trilobite fragments, at other places frag- 
ments from many sources were washed together and elsewhere 
the strata are crystalline without recognizable organic remains. 
TVenhofel, W. H., Bull. Mus. Comp. Zool,, vol. LVI, No. 4, 1916, p. 
' 341 . 
