On the Chalk Bluffs of Trimmingham. 305 



All these specimens are more or less like Hydradendrium 

 spinosum j but on one of them (no. 14. 6. 61. 2, without 

 name), which appears to have undergone better preservation 

 than^the rest, there is a thick light-brown sarcodic theca, which 

 is uniformly inflated at short intervals over the branches, so 

 as to present a succession of fusiform swellings averaging 

 about l-415th inch in their shortest diameter. When a bit 

 of the branch bearing one of these swellings, after having been 

 softened by soaking in spirit and water for twenty-four hours, 

 is placed under the microscope and examined with a 1-inch 

 object-glass, it may be observed to consist of a transparent 

 sarcodic base densely charged with opaque white granular 

 matter arranged in reticulated lines, which, on being further 

 magnified, viz. under 5-inch object-glass, presents a variety 

 of cellular forms in great plurality and of different sizes, 

 among which the most noticeable are : — 1, a discoid body 

 with crenulated margin and central circular area, about 

 5-6000ths inch in diameter; 2, a pyriform body about 6-6000ths 

 inch long ; and, 3, ovoid thread-cells about 3-6000ths inch in 

 their greatest diameter, together with other minute forms 

 which may or may not belong to a Penicillium with which the 

 sarcode is permeated. But it is the fusiform inflations them- 

 selves on the branches which command our attention most ; 

 for they appear to have contained the full-grown polyp, of 

 which, however, nothing now can be seen but a slight depres- 

 sion on the most prominent part here and there, bearing no 

 resemblance whatever to the radiated actinozoic form of the 

 polyp in the theca of a Gorgonia ; nor, as above stated, are 

 we likely to find any thing more, unless the specimen be seen 

 in its active living state in its own element, or after having 

 been properly preserved in spirit and water, in the manner of 

 that of Hydractinia echinata above mentioned. Dana's 

 figures apud Milne-Edwards {op. cit. Atlas, pi. C. 2. tigs. 

 5, 6) show nothing more than Ellis's, viz. that the polyp's 

 head has six tentacles. 



XXXVII. — The Chalk Bluffs of Trimmingham. 

 By A. J. Jukes-Browne, B.A., F.G.S. 



The existence of certain isolated masses or bluffs of chalk on 

 the shore near Trimmingham, in Norfolk, has long been known 

 to geologists. They are partially buried under the deposits 

 of the Lower Glacial series, which here form cliffs of consider- 

 able height, and founder down from time to time in great 

 landslips, so that a clear section from top to bottom is rarely 

 exhibited. Many writers have described these masses of 



