34G 



our list of Trenton forms were found numerous specimens of Beyrldiin, 

 PhoHdops and also Orthls insculpta, 0. 2}sctinella and 0. occidental-is. 

 Tlhynchonell» recurvirostra, Hall, oftimes referred to as a Zygospira, but 

 recently placed under the new genus Anazyga of tlie late lamented Dr. 

 Davidson, was found in very great abundance. Dahnanites Behryx o^ 

 Billings was also found here. 



The form referred to by Mr. Ami in his '•' last of the Cambro- 

 Silurian fossils of Ottawa, etc.," 1884, as Tetradiuni Peachii, var C ana- 

 dense, Foord, with a query (?) has since been thoroughly worked up 

 and examined with great accuracy by Prof. W, B. D wight of Vassar 

 College, Ponghkeepsie, N". Y. In the course of this very interesting 

 study, Mr. Ami had ample opportunity for nearly two years (since the 

 spring of 1883) of seeing the whole ]>rocess of elucidation, as it wa.s 

 developed in that well defined and eminently interesting organism. 

 Aft.u- careful examination it was definitely ascertained that the species 

 in question was unmistakably that which Mr. E. Billings had described 

 as Stromatopora compacta (Pal. Foss. Vol. I, p. 55) and the same 

 which Sir William Dawson very appropriately placed provisionally in 

 the genus Cha'tetes. Dudng his visit to Europe last fall, Mr. Ami made 

 it a point to consult Dr. Dybowski's work on " Die Cho;tetiden," etc., 

 wher« that Russian author hud described a iorm, Solowpora spongioides 

 of undoubted affinity and intimate likeness to Billings' Stromatopora 

 compacta. They were, no doubt, both referable to one species and one 

 sjiecific designation. It was then a question which had the priority, 

 Billings', Dybowski's, Nicholson and Etheridge's or Mr. Foord's. Mr. 

 Billings' name was prior by several years, and therefore his specific 

 reference will stand whilst the others fall to the ground. The genus 

 Solenopora, however, which Dr. Dybowtki had at the same time created 

 to receive his species S. spongioides will certainly stand and be accepted 

 as the recognised genus to which Billings' species must be referred. 

 This form then will be known as Solenopora compacta, Billings. The 

 greatest difficulty which had arisen was regarding the existence o' 

 tabula; proper. Some authors found the tabula^ to be absent altogetlier 

 (Dybowski and Foord), others very numerous (Dawson, Nicholson and 

 Ethe:"idge), but to Dr. W. B. Dwight is certainly due the credit of dis- 

 covering them in the winter of 188-1-5 in especially fine and well jire- 



