48 Correspondence — GrenviUc A. J. Cole v^' J. W. Evans. 



Eocene in this area was found to be marked by a strong uncon- 

 formity and overlap. This had never been previously recognized in 

 Egypt. In 1S98 the existence of thick bone-beds, probably of con- 

 siderable commercial value, was discovered in the Oasis of Dakhla. 

 Again, in 1897, in the Abu Roasch district, near the Pyramids of 

 Giza, the junction of the Cretaceous and Eocene was again found to 

 be unconformable, instead of being marked by lines of fault, as 

 formerly supposed. In the Western desert, and in one case in the 

 Eastern desert also, igneous intrusions have been discovered ;it 

 isolated spots in the sedimentary areas. 



This brief statement of a few of my own results is rendered still 

 more necessary in view of the fact that there are at the present time 

 several observers about to visit tlie same regions. The details con- 

 nected with these cpestions will probably be dealt with in the 

 Survey Memoirs. Hugh J. L. Beadnell. 



Cairo, 7th December, 1S99. 



ORGASTIC EEMAINS FEOM CAMBRIAN EOCKS OF BRAY. 



SiK, — The question of the age of the ancient beds of Bray and 

 Howth has recently attracted some attention in connection with the 

 additions to our knowledge of Cambrian and Pre-Carabrian rocks in 

 other places. The true nature of the real or supposed fossils in these 

 Irish beds is therefore an urgent one. Oldhamia has been obliged to 

 submit to a verdict of Not proven, at the best. It is naturally asked 

 whether Histioderma is to meet with a similar fate. Unfortunately, 

 inquiries from various workers elicited the fact that the tj'pe- 

 specimen was missing from the Irish Survey Collection. 



Recently, however, in rearranging the mineral collection of the 

 Royal College of Science for Ireland, we were fortunate enough to 

 find four specimens of Elstiodenna, with their original tablet ; these 

 have now been restored to the Survey Collection, and will be 

 exhibited in the Museum of Science and Art, Dublin. Two of the 

 specimens are the internal and external casts of the same object, the 

 former being the actual specimen figured as Histioderma Hibernicum 

 by Dr. J. R. Kinahan in his paper " On the Organic Relations of the 

 (Cambrian Rocks of Bray and Howth ; with Notices of the most 

 remarkable Fossils": Journ. Geol. Soc. Dublin, voL viii (1858), 

 pp. 68-72, pi. vi, fig. 2. 



A moment's examination of the actual specimens is enough \o 

 remove all doubt of the organic nature of Histioderma. It consists 

 of a cup-shaped expansion, with two sets of approximately jjarallel 

 lidges which intersect each other obliquely, and a conical root-like 

 continuation below. Without denying the possibility of the correct- 

 ness of Kinahan's explanation that the ridges represent the tentacles 

 of an annelid, we cannot help thinking that the general appearance 

 rather suggests that they are lines of thickening in a continuous 

 muscular envelope. Grenville A. J. Cole. 



John W. Evans. 

 Royal College of Science for Ireland. 

 December 16, 1899. 



