102 W. A. Bell — Mississippian Formations of 



Jonesina seems unfavorable to a fluvial or lacustrine 

 origin of the particular sediments in which it is found, 

 the remaining evidence is so overwhelmingly in favor of a 

 terrestrial deposition that it is believed a fresh-water 

 adaptation of this genus must be accepted. 



The accumulation and preservation of several thousand 

 feet of terrestrial sediments characterized by abundant 

 soil levels calls for a differential subsidence of the basin 

 of deposition. Two convergent lines of evidence ^ the 

 source of material in nearby upland masses lying in a 

 general soutlnvesterly direction. Primarily, the com- 

 position of the sediments points unequivocally to the belt 

 of Devonian granites and Precambrian slates and arkosic 

 quartzites of the Meguma series, w^hich outcrop at present 

 for 120 miles to the southwest before they sink beneath 

 the Atlantic. The second line of evidence is presented 

 by the alignment of the current ripples. By plotting the 

 results of many observations, the mean trends indicate 

 the dominance of currents from the southwest. 



Correlation. — The plant evidence has been effectively 

 summarized by David Wliite, who correlates the Horton 

 with part of the Pocono, assigning to it a Kinderhookian 

 age. The fish genera Eloniclithys and Rhadinichthys 

 establish the Carboniferous age of the deposits, whilst 

 the ostracods have their nearest allies in the Lower Car- 

 boniferous of Europe. 



Upper contact. — Although the Cheverie formation suc- 

 ceeds the Horton without angular discordance, a marked 

 disconformity is inferred. There is a distinct climatic 

 break and the thick clastic beds at the base of the Cheverie 

 suggest also a marked uplift of the headwater region that 

 was undergoing erosion. Moreover, local mountain- 

 making movements at this time are indicated by heavy 

 conglomerates of Cheverie age in the Moncton area, New 

 Brunsmck. 



Cheverie Formation. 



Description. — The Cheverie formation attains a maxi- 

 mum thickness in the district of from 600 to 800 feet. 

 The basal 300 feet is dominantly made up of gray arkose 

 grits with a subordinate amount of chocolate argillo- 

 arenaceous shale and occasional beds of micaceo-arena- 

 ceous shale of a greenish black color. The arkose consists 

 of angular fragments of transparent quartz up to 15 

 mm. diameter, with angular fragments of feldspar of 



