68 Dr. G. F. Mattheio—The Oldest Siphonofrefa. 



■who do not accept submergence. We are sorry our friend should 

 have indulged in ' such a fantastic supposition. Is not the bed 

 of the Firth of Clyde itself large enough to supply any marine 

 remains that may be in question ? Why go out to the Atlantic 

 for them ? The truth is, the whole evidence goes to show that 

 such was the congested and over-brimming condition of the 

 Firth of Clyde as one of the main outlets for the land-ice of the 

 country — the ice of the West Highland, Ayrshire, and Galloway 

 mountains, augmented by that of Arran in the Firth itself — that 

 a large section of the frozen stream was deflected westward across 

 Kintyre (exactly in the opposite direction figured by Mr. Eeade), and 

 so out to the Atlantic in that direction (see Brit. Assoc. Report, 

 Kintyre Shelly Clays, 1896). Finally, when the ice in the Firth of 

 Clyde was of such dimensions that it passed straight on over Bute, 

 the Cumbraes, and Ailsa Crag, where do we suppose its outer edge 

 lay in Ayrshire, or along the Ayrshire coast? Can we fix a nearer 

 point for it than along the flanks of the hills which divide Ayrshire 

 from Renfrewshire and Lanarkshire, where fragments of West 

 Highland rocks are numerous, and these patches of high-level shelly 

 boulder-clay are chiefly found ? 



V. — The Oldest Siphonotueta. 



By G. F. Matthew, D.Sc, F.R.S.C. 



(Read before the Natural History Society of New Brunswick, January 5, 1897.) 



ri"^HE ancient Brachiopodous genus SipJionotreta is well known 

 X by its species occurring in the Ordovician and Silurian strata 

 of Russia and Great Britain, and its peculiar pedicle opening has 

 been the subject of remark. The author is not aware that this 

 genus has hitherto been repoi'ted from any Cambrian terrain, and, 

 therefore, the greatest interest will attach to a form recently found 

 in the lower beds of the St. John Group, which is nearer to Siphono- 

 treta than to any other known genus. 



The new form is remarkable, so far as its pedicle passage is con- 

 cerned, in combining the two genera Siplwnotreta and ScMzamhon ; 

 for in its early stages it had the dorsal furrow of the latter genus, 

 but afterwards it developed the tubular passage seen in the former. 



This shell is older than any Paradoxides, being of the Protolenus 

 Fauna,^ and is found in strata that nearly correspond in age to the 

 beds which at another locality carry the related genus Trematobolus. 

 But while the new form abandoned the Schizambonal opening for 

 its pedicle, and adopted a contracted canal for the passage of this 

 organ similar to that of Siplwnotreta, Trematobolus maintained the 

 open fissure (or hole) through life. 



Young individuals of the new form of the size of ScMzamhon 

 typicalis, Walcott, are actual examples of the genus ScMzamhon. 

 The history of the growth of the species from the larval forms to 

 maturity is shown by exfoliated shells, in which the siphon stands 



1 Trans. New York Acad. Sci., vol. xiv, pp. 101-153. 



