464 
JOURNAL OF THE PLYMOUTH INSTITUTION. 
Before I proceed further, it will be advisable that I should again 
cite the opinions in regard to this section of Mr. Jukes and Dr. HolL 
Mr. Jukes, as already noted, suggests the " possibility of these 
beds, ' so like the Old Bed Sandstone,' which lie to the northward 
of Bovisand Bay, being brought up by an anticlinal, accompanied 
by inversion as well as contortion, and that this inversion may even 
affect the southern borders of the Plymouth limestone themselves." 
Messrs. Sedgwick and Murchison refer to the rocks of this section 
as bearing the closest resemblance to the rocks east of Coombe 
Martin; and upon this Mr. Jukes observes: "If the Coombe 
Martin limestones are on the same horizon as the Plymouth lime- 
stones, it is a strong argument in favour of inversion occurring at 
Plymouth, and that the sandstones which seem to be over the lime- 
stones there really come up from under them, as they certainly do 
in North Devon." Finally, referring to some of the contortions 
in Bovisand Bay, Mr. Jukes observes: "If beds could lie hori- 
zontally bottom upwards, for 25 yards, that inversion being only to 
be proved by the discovery of the small locality where the actual 
curvature of a distinct and recognizable bed happened to be ex- 
posed, what was there to forbid the possibility of beds lying in that 
position for 250 yards, or even 2,500, or more, and yet no direct 
evidence of that fact being anywhere accessible?"*' 
Dr. Holl takes the opposite view. " There appears to be on the 
east shore of Plymouth Sound, south of Mount Batten, and from 
the limestone of Brixham, along the river Dart, and the coast at 
Mann Sands, an upward series, though grey, blue, and purple 
slate, to the red grit, which rocks succeed each other conformably ; 
and the limestones of Berry Pomeroy and Marldon are overlain by 
variegated argillaceous slates, surmounted at Blagdon Cross by 
red grits like those of Staddon Point and the banks of the Dart. 
No similar rocks, however, are seen rising up from below the lime- 
stone among the lower rocks north-west of Dartington and Ogwell ; 
nor are any such again brought up to the surface from beneath the 
limestone in the long downward succession of the beds between 
Plymouth and the Horrabridge station on the Tavistock railway." j- 
Por my own part I hold that these rocks are really superior to 
the limestone, though I quite admit, and in fact believe, that here 
* "Notes on Parts of South Devon and Cornwall," pp. 18-22. 
f "On the Older Rocks of South Devon and East Cornwall."' Proe. Geo. 
Society, April, 1868. 
