3^3 



will be ill a more accessible and systematic form than it would other- 

 wise be. 



Whilst, during the past season, older formations than the Chazy 

 have been visited, it is not deemed expedient as yet to publish tlie 

 notes recorded, hence this report will begin with the 



Chazy Formatiox. — ThisCambro-Silurian or Ordovician formation^ 

 so extensivfly developed in the Ottawa Valley, and from which only 

 a very limited number of organic forms have as yet l)een obtained, wdll 

 in any careful and attentive examination of the various series of strata 

 which comprise its measures amply repay the observer. In the report 

 for 1883-84 reference is made to the lower measures of this formation, 

 which were observed on the occasion of the Club's excursion to Lake 

 Deschenes. The exposures referred to along the north shore of the 

 Ottawa River at that place, and between it and the railway track, 

 were pointed out as being almost destitute of fossils, that the only 

 fossiliferous rocks observed consisted of a band of ferruginous and rusty 

 weathering sandstone, two or three inches in thickness — some four feet 

 above lew water mark. From this a number of characteristic fossils 

 of the Chazy formation had been collected. (Trans. O.F.N.C., vol. I, 

 No. 4, p. 64.) 



During the past season, Mr. W. E. T. Sowter has traced this 

 same band in its westerly extension to the town of Aylmer, four miles 

 from I>eschenes Village, wdiilst the occurrence of the same band between 

 these two localities has also been ascertained by the sime gentleman. 

 At the wharf in Aylmer this characteristic band may be seen about a 

 foot and a-half above the lake level. 



This affords^ thei'efore, a good criterion from which to ascertain 

 the precise horizon of the measures at Aylmer and wheiever its occur- 

 rence may be signalled. A bi-achiopod — OrtJus iinjjerator, Billings — 

 is the most abundant and most easily recognised form, so that on 

 account of its prevalence this band will in future be referred to as 

 marking the zone of Orthis imperator. 



There is a small Rhynchonella associated with the above species. It ha.s 

 few plications or costfe but they are compai'atively large and angular, much 

 like R. oriental is, Billing.5, described from the Mingan Islands. The 

 forms under consideration agree very well with Hall's description and 



