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BRITISH DEVONIAN BRACHIOPODA. 



Middle Devonian. 



Geologists do not appear to me to have yet been able to establish the exact sequence 

 -of the various beds of limestone, shales, and sandstones, which appear to compose the 

 Middle Devonian group of Great Britain ; and a glance at the Twenty-second Sheet of the 

 ' Map of the Geological Survey' will show how very disconnected the limestones of the 

 district are, — so much so indeed that it appears even difficult to satisfy oneself of the 

 direction of the stratification or bedding at Ramsleigh, Woolborough, Barton, Lummaton, 

 and in some other places ; for in most localities the beds are so contorted, faulted, and 

 •even inverted, that it is hardly possible to venture upon even an ideal stratigraphical 

 section. Palaeontology can alone guide us in this difficulty ; and I am glad to state that, 

 through the kindness of several friends, I have been able to assemble and examine several 

 thousand specimens of the Middle Devonian Brachiopoda from the counties of Devonshire 

 and Cornwall. Unfortunately, however, by far the larger number of specimens are found 

 in a very imperfect state of preservation, and are often much distorted, but it is quite 

 possible to procure tolerably perfect examples of the larger number of the species. The 

 Middle Devonian beds and fossils of North Devon having been already described, we 

 need not allude to them again. We have at Mr. Pengelly s suggestion in the accom- 

 panying table, united Bradley, Chircombe Bridge, and Ogwell, into one column, under 

 the name of " Chircombe Bridge," because in fact there is no such fossil-locality as 

 Chircombe Bridge at all. It is simply, says Mr. Pengelly, a small bridge across the little 

 River Lemon, a tributary of the Teign, which it joins at Newton. The Ogwell quarries 

 (there are two, Westhill and Ivy Green) are on the right or south bank of the stream, 

 and Bradley quarry is on the left bank. These quarries are about within a stone's throw 

 of one another, and of Chircombe Bridge. When a geologist uses the words "Chircombe 

 Bridge/' he means Bradley, or Ogwell, or both. 1 At Bradley and Ogwell the limestone 

 beds dip at about 20° towards S. 39° E. ; and therefore strike about S. 51°W. and 

 N. 51° E. At the village of East Ogwell there are numerous interstratitied, and there- 

 fore contemporary, beds of ash and slate, apparently conformably overlying the limestones 



1 There are limestones above the Ogwell Shales, viz., the Great Limestones of Bradley and Ogwell ; 

 the passage-beds being well exhibited between Ogwell House and the park ; and a small patch of limestone, 

 at West Ogwell village, appears to be included in them; along the line of junction about a mile N.E. 

 of Chircombe Bridge. 



I am informed by Mr. Pengelly, that Kamsleigh (not llamsleugh) is situated between Ogwell and 

 Woolborough. If we were sure of an unbroken sequence (which we very certainly are not), the Ramsleigh 

 beds would be far above those of Ogwell and Bradley, and below those of Woolborough. Lithologically 

 they resemble the Woolborough beds rather than those of Ogwell ; but they have very few fossil Zoophytes 

 in common ; whilst the Ogwell, Bradley, and Woolborough beds have a large number of Corals and 

 Sponges in common. 



