186 Correspondence — Rev. /. F. Blake. 



portion of the Downs to the height of 600 feet, that is if the pehhles found on the 

 crest of Cisbury are what they appear to be, of 'I'ertiary origin. He considered there 

 was no evidence from surface indications that the northern portion of the Downs has 

 ever been submerged since its upheaval. Historical documents, submerged forests 

 along the whole coast-line, and the shallowness of the sea-bottora afford evidence that 

 the sea has greatly encroached upon the land at this part of the coast. The site of 

 Old Brighton was stated to be seaward between East and West Streets, and not, as 

 Lyell states, where the Chain Pier now stands. The coast-line at the period when 

 the Brighton valley was an estuary of the sea and a river was very different from 

 what it is now. The "Level" was then covered with water, and waves dashed up 

 beyond the site of St^ Peter's Church, as pi-oved by pebbles like those on the present 

 beach being there found in sewer excavations. 



The geological formations at Brighton were stated to be six, viz. Silt in the valley. 

 Brick -earth of Hove, the Elephant-bed, Temple Field deposit. Plastic Clay of Furze 

 Hill, and the Upper Chalk. The present paper embraced the author's observations 

 of the first three. In the lower portion of the Silt and the Coombe-rock beneath it 

 are imbedded immense numbers of water-rolled, sandstones similar to the Sarsen 

 stones distributed over the surface of the Downs, but whether of Wealden or Tertiary 

 origin is unknown. The Brick-earth is a later formation than the Elephant-bed, 

 upon which it everywhere rests; though the organic remains found in it are the 

 same, viz. remains of the elephant, horse, red-deer, whale, and shells of an arctic 

 type. If, as Mr. Godwin-Austen tells us, Brick-earth is the "wash of a terrestrial 

 surface," how are we to account for the marine remains imbedded in it? The pebbles 

 of Palaeozoic rocks found in the old sea-beach underlying the Elephant-bed were 

 stated to have come from France, when that country was united to this island, having 

 travelled a beach once extending from Brighton to Calvados. This was supported by 

 the observation of the author of how pebbles travel along coasts assisted by sea- 

 weed, whose roots are attached to them. In concluding his paper, Mr. Howell 

 opposed the opinion formed by the Geological Section of the British Association 

 during their visit to the Kemp Town section of the Elephant-bed, that this re- 

 markable deposit was due to ice action, and considered the opinions of Webster, 

 Mantell, and Lyell, corroborated by the fact that the materials composing the bed 

 are all water-worn. 



OOS-iaESIPOIl^X^EJiTOIHi. 



THE OLDEST KNOWN BRITISH TRIGONIA. 



Sir, — The claim of T. Lingonensis to this title does not rest on the 

 York specimen, but on several that have been found and recognized 

 in situ. This is all the public can care to know ; but as I identified 

 the specimen in our Museum, you may allow me to add that it is 

 not "an undoubted Inferior Oolite fossil." The Dogger of the Peak 

 is very similar to the Eston Ironstone, in hand specimens ; but any 

 one familiar with both could easily distinguish them. Mr. Leckenby 

 is proba,bly not familiar with the latter — as there are few, if any, 

 fossils from it in his magnificent Lias collection — unless he has 

 them labelled from the Inferior Oolite. One is reminded of a remark 

 long ago made by Williamson, that Yorkshire geology has suffered 

 from the fossils being collected miscellaneously, and their horizon 

 judged of by their matrix. J, F. Blakb. 



Clifton, Yobk, March 6ih, 1873. 



