THE GEOLOGICAL STRUCTUEE OF SOUTH CORNWALL. 265 



can be obtained there is a regularity of strike and inclination, 

 which precludes the possibility of any unconformability in this 

 neighbourhood. 



There are many exposures of rocks of the same ages 

 occurring on the north coast of the county, which as yet I am 

 not acquainted with from observation, but Mr. Collins makes no 

 mention of unconformabilities in this region, neither am I aware 

 that any such have been noted by other observers, which 

 inclines me still further to doubt their existence in toto. 



If a line be drawn on the map beginning from the granite 

 at Penryn, and ontinued in the direction of Pendennis Point, 

 or to the coast at Grerrans Bay, it will be found that the line 

 will pass through a rising section of strata from the lowest beds 

 which incline againsi the granite at Penryn up to the highest 

 beds exposed, wirhout any of the alleged unconformabilities 

 occurring, so that there is a most complete unity throughout 

 the whole series of strata. 



It will thus, at once, I think, be clearly seen that we have 

 no reasona.ble evidence to justify us in breaking up these beds 

 into two distinct and well-defined formations. I would therefore 

 cancel the term Cambrian as applied to this series of strata, and 

 associate the whole of these rocks simply as a lower portion of 

 what Mr. Collins regards as Lower Silurian, to the consideration 

 of which we will now pass. 



Lower Silurian — I quite agree with Mr. Collins in removing 

 the strata exposed around Falmouth and its neighbourhood from 

 the Devonian as at present laid down on the maps of the 

 Greologieal Survey, and transposing them to the Lower Silurian, 

 although the survey is quite correct in colouring as Lower 

 Silurian that portion of the strata at Veryan Bay, which 

 Sedgwick explained as being an inverted portion of that for- 

 mation resting upon the Devonian. With regard to these 

 Lower Silurian beds as described by Mr. Collins, I have but few 

 remarks to make, as his observations are not of an extensive 

 nature, being principally confined to a few general aspects which 

 are in the main correct enough. 



There is, however, one point on which Mr. Collins has, I 

 think, committed a very serious blunder. He has separated the 



