150 Intelligence and Miscellaneous Articles. 



(cbarriages), and the dirt'erent courses of the old gold-bearini!: 

 streams, which gradually passing to lower levels, reach the great 

 areas of basalt, under which they continue their hidden course. To 

 illustrate these points, the author prepared and sent a MS. map of 

 the district from beyond Buninyong to Creswick, on which the 

 granite, basalt, schists, and quartz-lodes were shown, as well as the 

 gold-channels, gullies, runs, leads, &c., connected with which 96 

 named spots or diggings were carefully indicated. 



2. Description of a New Species of Cephalaspis (C. Asterolepis) 

 from the Old R.ed Sandstone of the neighbourhood of Ludlow. By 

 John Harley, Esq. Communicated by Prof. Huxley, F.G.S. 



This new form of Cephalaspis (from Hopton Gate) is at least twice 

 the size of C. LyelUi, and is further characterized by the position, 

 obliquity, and magnitude of the orbits. The space between the 

 orbits is proportionally small, and the occipital crest very short. The 

 outer enamel-layer is ornamented with tubercles, which, though 

 somewhat variable, bear so close a resemblance to those covering the 

 bony plates of Asterolepis, as to have suggested the specific name. 

 The inner layer of the bony plate presents lacunae and canaliculi, 

 resembling those of human bone ; and many of them, in the sjiecimen 

 described, are naturally injected with a transparent blood-red mate- 

 rial, so distinctly and delicately, that in their minutest details the 

 structure of canals not more than t^xtuTTu^^ °^ ^'^ '\ncA\ in diameter is 

 beautifully revealed. 



Mr. Harley also described a more perfect specimen of Cephalaspis 

 Salu-eyi than the one on which Sir P. Egerton not long since deter- 

 mined the species. It M'as found by Mr. Sahvey at Hinstone near 

 Bromyard. Associated with the C. Salicei/i, the author found a 

 specimen of either a dermal plate or a tooth of a placoid fish, re- 

 sembling some Silurian fossils called Calolepidce by Pander. 



XXII. Intelligence and Miscellaneous Articles. 



NEW 5IETHOD OF EXAMINING AND VERIFYING THE SPECIFIC 

 GRAVITY OF BODIES. BY M. A. MEYER. 

 ^"^HE methods at present in use for the determination of specific 

 -■- gravities are very exact, but at the same time very complicated. 

 As the whole question consists in facilitating the means of measuring 

 exactly the volume of water equivalent to the volume of the sub- 

 stance experimented upon, the problem may be solved in a very 

 simple, but at the same time sufficiently exact manner, by operating 

 as follows : — After having filled a vessel with water, the long leg of 

 a reversed siphon is inserted ; the liquid runs out for a moment, 

 but comes to a stand in the tube if the apparatus remains tranquil. 

 The body of which the specific gravity is to be determined is then 

 immersed, and the water recommences to run out by the siphon. 

 Collected in a small receiver, this water represents the exact volume 

 of the body. 



