'^28 CEPHALOPODA FROM THE CROSS FELL INLTER. 



in such a manner as to displace the siphunclc, bending it and 

 forcing it towards the opposite side. No estimate can be made of 

 the size of this fossil, the body-chamber being absent in all the 

 specimens collected. 



Three crushed and weathered fragments from the same locality 

 ond horizon, but somewhat larger than those just described, have 

 similarly close-set septa and a beaded siphunclc, and they most 

 probably belong to the same species. 



The present form agrees with Ortlioceras (? Actinoceras) mendacv, 

 Salter *, in the close proximity of its septa, but differs therefrom in 

 its more rapid rate of tapering. The test not being preserved in 

 the specimens from the Durness Limestone, upon which Salter's 

 species was founded, no comparison can be made between the two 

 species as regards this feature. It will be better therefore to 

 regard it, provisionally, as new. 



4. Cyrtoceras (?). 



Pragmentar}'^ casts of the peripheral part of a small curved shell 

 from Eoman Fell exhibit septal characters similar to those of 

 Cyrtoceras (Phragmoceras, Portl.) incequiseptum, Portlock t, sp., from 

 the Bala Beds of Desertcreat, Co. Tyrone. These specimens are too 

 imperfect for description. 



Discussion. 



Prof. Boyd Dawkins said that the case cited by Mr. Marr of a 

 fault having been in course of development at different geological 

 periods is by no means an isolated example. Many faults show 

 signs of movement at different ages. The Thousand-yards Pault, for 

 example, passing up the valley of the Irwell to the jST.W. of 

 Manchester, shows a throw of 1000 yards in the Coal-measures, but 

 very much less in the Permian and Triassic strata thrown down to 

 the north. With regard to the phyllites, the phyllites of the Isle 

 of Man form a linl^: between the clay-slates on the one hand and 

 mica-schist on the other. 



Dr. Hicks asked whether the term " Bala," as used by the 

 Authors, included any typical Llandeilo rocks ; or whether it was 

 confined, as he thought it ought to be, to such rocks as are classed 

 under that name in North Wales. The section on the wall 

 appeared to show a continuous succession from the Skiddaw Slates to 

 Upper Silurian. He would be glad to know whether there was clear 

 evidence of continuous deposition in the area generally ; and whether 

 there was no evidence of a break between the beds which had been 

 recognized by Mr. Goodchild as of Tremadoc age and the ov6rlying 

 Arenig beds. 



With regard to the faults shown- on the map, he would like some 

 explanation as to how the Authors accounted for the fact that they 

 appeared repeatedly to cross the higher beds without affecting the 



* Quart. Journ. Geol. Soc. vol. xv. (1859) p. 374, pi. xiii. fig. 24, a, h. 

 t * Geology of Londonderry ' (1843), X3. 382, pi. xxviii. a. figs. 4 a, 4 6. 



