32 REPORT — 1860. 



Report on the Excavations in Dura Den. 

 By the Rev. John Anderson, D.D., F.G.S. 



In reporting on the operations and researches in Dura Den during the 

 summer of 1860, the Committee laid open several large sections of super- 

 incumbent boulder clay and of the underlying yellow sandstone, but were 

 unsuccessful in obtaining any of the Pamphractean or Pterichthyan forms 

 sousiht after. None of the workmen eiiirasred in the excavations in 1837, 

 when these organisms were found in great numbers, were living in the di- 

 strict ; and the Committee, proceeding on the information of others, failed to 

 detect the precise fossiliferous bed in question. Their labours brought them, 

 however, to a point which cannot be far distant from these crustacean trea- 

 sures, and they are hopeful that, on resuming their researches, they shall 

 meet with the desired success. They proceeded to other sections of the rock, 

 in the bottom of the ravine, and there they were richly rewarded with an 

 abundance of the fossil remains of fishes, chiefly of the genus Holoptychius 

 and other Cozlacanths. 



The yellow sandstone deposit, as described in the 'Course of Creation' 

 in former papers of Dr. Anderson, consists of an alternating series of grits, 

 shales, marls, and fine-grained sandstone, of various shades of colour. The 

 fossil fishes are confined to one particular bed, which, when laid open, easily 

 splits up, the organic materials determining the point of separation, and 

 exhibiting often on a single flag from fifty to a hundred closely-packed and 

 well-defined figures with scales, fins, and cranial plates quite entire. On the 

 present occasion your Committee were surrounded by an intelligent group of 

 lovers of the science, male and female, from Edinburgh, St. Andrews, Forfar, 

 Dundee, and Cupar, and succeeded, after a few hours' labour, in displaying to 

 their eager gaze some of the largest and most beautiful specimens of these 

 older denizens of our seas. 



It will not be necessary to describe in detail any of the well-known forms 

 and characteristics of Holoptychius, the most abundant of the genera found in 

 this deposit. But having submitted some of the most perfect of the spe- 

 cimens to Professor Huxley, and as he thereby was enabled to detect some 

 new particulars connected with the structure and figure of the genus, it will 

 not be deemed out of place to give an abstract of his interesting descrip- 

 tion, contained at length in Dr. Anderson's ' Monograph of Dura Den*.' 



"In studying," says Professor Huxley, " the new forms of Devonian fish 

 which have been described, I found it desirable to obtain a more definite 

 conception than was deducible from extant materials, of the characters of 

 Holoptychius. To this end I examined a considerable number of specimens 

 of Holoptychius Andersoni, contained partly in the collection of the British 

 Museum, partly in that of the Museum of Practical Geology, and I have 

 arrived at the following conclusions. Holoptychius Andersoni has very nearly 

 the proportions of a carp, but its body is thicker and its snout is more rounded 

 from side to side. The greatest depth of the body is in front of its middle; 

 the length of the whole body is to that of the head nearly as five to one. 

 The orbit is nearly circular, about one- fourth the length of the head. The 

 cranial bones all exhibit a peculiar granular structure. The two parietals 

 occupy a large extent of the upper wall of the cranium, and have the form 

 of pentagons with their elongated bases turned inwards and applied to one 

 another. The occipital region is covered by three bones, one median, and 

 two lateral; the lateral bones having radiating stria? on the posterior halves 



* Dura Den ; A Monograph of the Yellow Sandstone and its remarkable Fossil Remains. 

 By the Rev. J. Anderson, D.D., F.G.S. Edinburgh : Thomas Constable and Co. 



