\2-2 



In Older to ascertain definitely the tnie horizon of the Siphonotreta 

 in question, it was necessary to find it in situ, and further to obtain 

 from the same bed or bads in which it occurs as many species of fossils 

 as possible, in other words, determine what were its contemporaries. 

 It had been previously pointed out that the lowest measures of the 

 Utica formation about Ottawa consisted in a series of impure bands of 

 limestone at times, slightly dolomitic and interstratified with black 

 brittle bituminous shales all abounding in fossils. (See Geological 

 Report, Transactions Ottawa Field-Naturalists' Club, Vol. I. No. 4, 

 p. 66 ; also Vol. II, p. 347). The close resemblar.ce in lithological 

 character between the specimens sent to Dr. Davidson by Mr. 

 Whiteaves and the rocks constituting the lower poriion of the Utica 

 formation where it crops out along the right bank of the Rideau River, 

 opposite the Rifle Range, near the rapids, was such as to warrant a 

 careful search for SiphonotreUc in that locality. After a somewhat 

 careful searcli on tlie part of tl;Ose members of the Club above men- 

 liaed, a goodly number of specimens of this interesting species were 

 found at the rapiJs along with other forms to be mentioned later on. 



The precise bed in which Siphonotreta Seotlca occurs, is that band of 

 impure bituminous limestone, black or dark brown in colour, which 

 crosses the Rideau River at this locality and forms the rapids or slight 

 fall, giving the peculiar orographic aspect to that portion of the river 

 Avhich it possesses and dividing the smooth flowing water above this 

 point stretching on to near Ilurdman's Bridge from the rapid running 

 waters below. 



The following is a section of the measures of the Utica formation 

 exposed at the head of the rapids opposite the Rifle Range, and in- 

 cludes the zone of Siphonotreta Scotica. The middle and upper 

 measures of the Utica have been denuded away, especially during glacial 

 ;times, and the uppermost beds of the section are capped with Post- 

 .Tertiai-y deposits made up for the most part of debris of the ' till ' and 

 ^-ixica-va sand and associated gravel formations with 'erratics' in 

 abundance, the ' Leda clay' having been washed away in latter times. 

 The section is given in descending order : 



