27G 



ing' states that in New York during the early Stones River time deposi- 

 tion was confined to tlie Cliamplainian trough, and following the retreat 

 of that sea to the northwest into the St. Lawrence Gulf at the close of the 

 Crown Point stage, the Gulf of Mexico Embayment came into central New 

 York from tlie south, bringing in species and genera similar to the southern 

 interior faunas. During the upper Pamelia time the gulf connections were 

 restricted and somewhat later the sea was drained from the New York 

 region and the Champlain trough became again the area of deposition dur- 

 ing the upper Chazyan (Valcour stage). 



BRYOZOAN FAUNAS OF THE STONES RIVER GROUPS 



The earliest known bryozoan, Heteronema priscum, is a ctenostomatous 

 form and occurs in the Ungulite sandstone at Jegelecht Falls, Esthonia. 

 Russia. In Sweden this standstone has been referred to the basal Ordo- 

 vician by Swedish geologists from the presence of the fossil Ohohia (iixjIUnis. 

 The earliest American form is a species of Nicholsonella from the Beek- 

 mantown of Arkansas. Following these occurrences in chronological suc- 

 cession comes the earliest prolific fauna of tlie' Stones River limestone in 

 central Tennessee. Considerable work has been done on the bryozoan faunas 

 of the early Mohawkian beds that occur in different places in North 

 America but up to this time very little has been published. The description 

 of several species collected from the Stones River of the Central Basin 

 area in Tennessee and published in the "Final Report of the Geological and 

 Natural History Survey of Minnesota.'' Volume :!. 1893. by E. O. T'lrich, is 

 the most important paleontological contribution. The published work on 

 the bryozoan fauna in other localities has been of a general nature and in 

 many cases the author only suggested that a considerable fauna of bryozoa 

 was indicated by the numerous fragments of this class of fossils. In other 

 cases collections containing abundance of bryozoa have been made and laid 

 aside until more time was available to study them. The pi'esent report 

 is the most extensive publication up to this time based upon new and de- 

 scribed forms of the Stones River bryozoa. The full value of the work can- 

 not be realized initil the fainias of other areas have been studied in detail 

 and some of the conclusions reached may be modified when the information 

 from other areas is available. Considerable work has already been done 

 by the writer upon tlie bryozoa from the Chazy of New Yttrk which will 

 form the basis of a subsequent paper. 



Murfreeshoro fauna. The bryozoa collected are few and poorly preserve<l 

 and it is only the large trepostomatous species that can be identified from 

 the exterior surface, which are included in the table showing the range 

 and distribution of all the Stones River forms. The interior structure of all 

 of the observed specimens is destroyed by silicification. No gteuostomata 

 are reixirted from the Murfreeshoro or later divisions of the Stones River. 



Pierce fauna. Bryozoa are very abundant in the Pierce limestone. The 

 Order Cyclostomata is represented by five genera and nine species. All 



^Geol. Soc. of Amer. (1901). 

 ^Reference table, page 308. 



