448 J. Hophinson — On Uliabdopliora. 



Upper and Middle Devonian was thought to he marked hy a recon- 

 structed felsitic rock exposed at Bittadon, where it occupies that 

 position in the series. Professor Bonney. in a recent article in the 

 Geological Magazine, pointed out the intrusive character of 

 this rock as exemplified in the Bittadon section, and with his 

 determination I agree. No long extended line of igneous rock is 

 visible throughout the area, but in the vicinity of the horizon it 

 occupies at Bittadon the rock has been observed in several places. 

 I have observed it near Office Farm on the east of Bray valley (in 

 Sheet 27) at the junction of the Upper and Middle Devonian ; and in 

 two places in Sheet 20, between Winsford and Withil Florey, viz. at 

 Armoor Farm in the upper beds of the Middle Devonian slates, and 

 near Farmers Farm in the Middle Devonian at some distance from 

 the Upper Devonian Boundary, its position being probably affected 

 by faults. My friend Mr. Townshend Hall has kindly furnished 

 me with the following additional localities in Sheet 27, viz. between 

 Ashelford and Honeywell Farms, where the felsite was exposed in 

 a well section and road cutting at the junction of the Upper and 

 Middle Devonian ; and at Smitha Park in the upper beds of the 

 Middle Devonian near their faulted junction with the Upper 

 Devonian on the east of Loxhore. Sir B. Chichester informed Mr. 

 Hall that he had met with the felsite at Arlington. Between 

 Cockercomb and Adscombe on the Quantocks, Sheet 20, a fine 

 quarry exposes a patch of greenish trap ash rock apparently in 

 faulted basement beds of the Middle Devonian slate series at their 

 junction with the Hangman grits. 



In Hestercomb Park (south part of the Quantocks) a patch of 

 sj^enite occurs in the upper part of the Middle Devonian slate series. 



Y. — On some Points in the Morphology of the Khabdophoea. 

 By John Hopkinson, F.L.S., F.G.S. 



PEOFESSOE M'COY, in his "British Paleozoic Fossils" (1854), 

 speaks of transverse diaphragms being present at the base or 

 proximal termination of the calycles (hydrothecas) of certain grap- 

 tolites, dividing the calycles from the common canal or perisarc. No 

 further allusion appears to have been made to the presence of any 

 diaphragms or septa until in 1868 the writer mentioned (Journ. 

 Quek. Micros. Club, vol. i.) having observed " an impressed line 

 between the hydrothecEC and the periderm " (perisarc), which was 

 compared with that " at the base of the hydrothecaj in the Sertula- 

 riadse." More recently Professor Allman (Monogr. Tubularian 

 Hydroids, 1872), not admitting the presence of any septum or con- 

 striction, has compared the calycles of the Ehabdophora to the nema- 

 tophores of the Plumularidge. 



A few days ago I examined an extensive collection of grap- 

 tolites made by Mr. W. Kinsey Dover from the Skiddaw Slates, 

 amongst which are a few specimens from Falcon Crag showing 

 internal structure, most clearly seen in Didymograptus nitidus and 

 patidus, and Tetragraptiis serra. In several specimens of these 



