HARDWICKE' S SCIENCE-GOSSIP. 



43 



A Silver Ammonite. — Among some specimens 

 from the silver mines at Caracoles, South America, 

 examined at Paris by M. Jannettas, is an extraordi- 

 nary example of an Ammonite transformed into 

 native silver. It was found with a number of other 

 Ammonites belonging to the two species, A. per- 

 armatus, and A. plicatilis, but the latter were not 

 mineralised with silver salts. The silver Ammonite 

 in question has been entirely replaced by chloride of 

 silver, which has been partly reduced to the metallic 

 condition. It is therefore inferred that the silver ore 

 in the Caracoles mines may have been reduced from 

 a state of chloride at a period not earlier than the 

 deposition of the Oxford clay. 



Artificial Diamonds. — A not uncommon sensa- 

 tional story has been going the round of the news- 

 papers, to the effect that some fine artificial but real 

 diamonds had been manufactured at the St. Rollox 

 works, Glasgow, and that they had been tested 

 by Professor Maskelyne, who had declared them to 

 be genuine diamonds. In contradiction to this story, 

 Professor Maskelyne writes to "Nature" to say 

 that a few crystalline particles of so-called "artificial 

 diamonds " were sent him, the largest of which was 

 about 35 inch long. These were submitted to 

 mechanical, optical, chemical, and blow-pipe tests, 

 and Professor Maskelyne declares them to be "not 

 diamonds at all, but to consist of some crystallised 

 silicate, possibly one resembling an augite." 



The Physical History of the Chalk Flints. 

 - — At a recent meeting of the Geological Society, a 

 paper on this subject was read by Dr. Wallich. The 

 author described the origin, the mode of formation, 

 and the cause of the stratification of the Chalk flints. 

 Taking as the basis of his conclusions the fact 

 brought to notice by him in i860, namely, that the 

 whole of the protozoan life at the sea-bed is strictly 

 limited to the immediate surface-layer of the muddy 

 deposits, he pointed out in detail the successive stages 

 of the flint-formation, from the period when the chief 

 portion of the silica of which they are composed was 

 eliminated from the ocean-water by the deep-sea 

 sponges, to the period when it became consolidated 

 in layers or sheets conforming to the stratification of 

 the chalk. In relation to this subject the author 

 claimed to have sustained the following conclu- 

 sions : — 1. That the silica of the flints is derived 

 mainly from the sponge-beds and sponge-fields, which 

 exist in immense profusion over the areas occupied 

 by the Globigerine or calcareous "ooze." 2. That 

 the deep-sea sponges, with their environment of 

 protoplasmic matter, constitute by far the most 

 important and essential factors in the production 

 and stratification of the flints. 3. That, whereas 

 nearly the whole of the carbonate of lime, derived 

 partly from foraminifera and other organisms that 

 have lived and died at the bottom, and partly from 



such as have subsided to the bottom only after death, 

 goes to build up the calcareous stratum, nearly the 

 whole of the silica, whether derived from the deep- 

 sea sponges or from surface protozoa, goes to form 

 the flints. 4. That the sponges are the only really 

 important contributors to the flint-formation that live 

 and die at the sea-bed. 5. That the flints are just 

 as much an organic product as the chalk itself. 

 6. That the stratification of the flint is the immediate 

 result of all sessile protozoan life being confined to 

 the superficial layer of the muddy deposits. 7. That 

 the substance which received the name of " Bathy- 

 bius," and was declared to be an independent living 

 moneron, is, in reality, sponge-protoplasm. 8. That 

 no valid lithological distinction exists between the 

 chalk and the calcareous mud of the Atlantic ; and 

 pro tanto, therefore, the calcareous mud may be, and 

 in all probability is, "a continuation of //^chalk- 

 formation." 



Undescribed Fossil Carnivora from the 

 Sivalik Hills.— Mr. P. N. Bose has just given 

 a description of some fossil carnivora from the 

 miocene of the Sivalik Hills, in the collection of the 

 British Museum, but which have hitherto been 

 undescribed. The communication contained de- 

 scriptions of nine species of carrjivora from the 

 ossiferous Sivaliks, together with an introduction, in 

 which the age of the Sivalik fauna, and several 

 matters of general interest, were briefly discussed. 

 The species described were : — Alachcerodus sivalensis, 

 M. pahcindicus, Felis grandicristata, Hyixna sivalensis, 

 H.felina, Viverra Bakerii, Lutra paheindica, Cam's 

 cnrvipalatus, and C. Cautleyi. Canis eurz'ipalalus 

 is so named on account of the curvation of the palate. 

 C. Cautleyi is closely allied to the wolf, as is Viverra 

 Bakerii to the civet. The form of the forehead is 

 peculiar in Lutra palceindiea. In the form of the 

 skull, the dimensions of the upper tubercular, &c, 

 Hycsna sivalensis approximates to the living Indian 

 hyaena {H. striata) : but, in the absence or extremely 

 rudimentary character of the postero-internal cusp in 

 the lower carnassial, as well as in the entire absence of 

 the anterior accessory cusps in the upper and the first 

 two lower premolars, the Sivalik species comes closer 

 to H. m crocata. H. felina differs from all other 

 species of hyaena, living or extinct, in the absence of 

 the upper premolar 1. Felis grandicristata, which 

 was of about the same size as some of the larger 

 varieties of the royal tiger, had the sagittal crest 

 even more prominent than the F. cristata of Falconer 

 and Cautley. Machcerodus sivalensis was of about 

 the same size as the jaguar. One of the specimens, on 

 which this species is based, shows two molars in the 

 deciduous dentition instead of three (as in the genus 

 Felis). M. pahcindicus was considerably larger than 

 M. sivalensis. Both differ from all other known 

 species of Machcerodus in the form of the lower 

 jaw, &c. 



