BY W. N. BENSON. 579 



that there is often a distinct alteration, a bleaching and induration 

 of the mudstone at its contact with the tuff, and that it does not 

 involve the action of a kind of steam-blast all along the line of 

 contact of the claystone and tuff subsequent to their deposition, a 

 process of which it is extremely difficult to conceive, or of which 

 there is no evidence beyond the facts already mentioned. The 

 absence of steam-cavities may be accounted for, on either hypo- 

 thesis, by the crushing into the vacancy of the plastic tuff and 

 shale, and the complete escape of the steam favours the new sug- 

 gestion. 



It should be noted that, if this explanation is true, either the 

 mud must have been deposited in a very shallow sea, or the tuff 

 must have fallen in such great quantity as to protect the lowest 

 layers from immediate quenching by the seawater. There is little 

 sign, apparently, of the tremendous disturbance that the latter 

 alternative would necessarily have involved. 



Above this, the breccias are seen to be interbedded with a con- 

 siderable amount of banded claystone. The lower portion of this 

 mass is best observed in the valley of Swamp Creek, the upper in 

 the tributaries of Happy Valley, draining the Frenchman's Spur. 

 Oaken ville Creek also is in this series, for the most part. The brec- 

 cias incline to be coarse, more so in the upper portions, and con- 

 tain large fragments of banded chert. Occasionally they are so 

 coarse-grained as to resemble the finer portions of the Baldwin 

 Agglomerate, and possibly the narrow band of this rock, at the 

 top of the Upper Tuff-breccias, may be considered the representa- 

 tive of the Baldwin Agglomerate in this neighbourhood. This 

 does not, however, seem necessary. 



In the upper portions of the series also, are bands of claystone 

 containing Lepidodendron australe, radiolaria being found also in 

 the fossil specimens. These occur on the main road, about one mile 

 south of the Swamp Creek Bridge (G.L.,342). 



Stratigraphy. — The five divisions of the Bowling Alley Series 

 seem well substantiated; nevertheless, the great similarity of the 

 Series below the limestones, to those above the limestones, is so 

 suggestive of a wholesale repetition by strike-faulting (as is known 



