HARDWICKE'S SCIENCE-GOSSIP. 



93 



the crystal, giving rise to metallic reflections or a 

 play of colour." He further stated that schillerized 

 forms are produced by deep-seated hydration, 

 weathered forms being due to hydration near the 

 surface. 



A Crinoid with Articulating Spines. — In 

 the March number of " The Annals and Magazine of 

 Natural History," may be found an account of a new 

 species of crinoid from calcareous shales of middle 

 Devonian age at Arkona, Province of Ontario, 

 Canada, collected and described by Dr. G. J. Hinde, 

 F.G.S. The author refers to the description in 1SS3, 

 by Professor H. S. Williams, of a crinoid with 

 movable spines, to which the name of Arthroacantha 

 Itkacensis was given from Devonian strata at Ithaca, 

 in the State of New York. Of this, impressions only 

 were found, while Dr. Hinde's specimens were 

 fragments themselves. This new species, which was 

 found at a lower geological horizon than those of 

 Professor Williams, Dr. Hinde has named Hysiri- 

 crinus (= Arthroacantha) Carpenter/, and he says that 

 his specimens " conclusively show that Professor 

 Williams had correctly interpreted the impressions 

 and casts of the spines and plates in the Devonian 

 shales, and that, however, novel the feature of 

 movable spines may be in the history of the 

 Crinoidea, no doubt can be entertained of the fact." 



Silurian Insect and Scorpions.— The following 

 is taken from some Notes contributed to the " Geo- 

 logical Magazine," by Mr. Herbert Goss, F.G.S. 

 Till lately fragments of neuroptera found in Devonian 

 rocks of North Brunswick were the oldest known 

 insect fossils. Recently the wing of a cockroach 

 (Blatta) has been found in middle Silurian rocks at 

 Jurques, Calvados, France, and to this, the oldest- 

 known insect, and oldest-known terrestrial animal, 

 the name of Pahvoblattina Douvillci has been given. 

 Recently also two scorpions, insectivorous animals, 

 whose presence furnishes additional evidence of that 

 of insects, have been found in Silurian rocks, one 

 from the Ludlow beds (upper Silurian) of Lesma- 

 hagow, Lanarkshire, and the other from the upper 

 Silurian of the isle of Gotland. The latter, which 

 has been named Palccophonus nuncius, is said to have 

 been clearly an air-breathing animal, and to have 

 observable in it " the presence of four pairs of thoracic 

 legs, which are stout and pointed like those of the 

 embryos of many tracheata, and of forms like 

 campodea. This form of the leg no longer exists in 

 the fossil scorpions of the Carboniferous formations, 

 in which fossils these appendages resemble those of 

 existing species." 



Coral-stone converted into Phosphate of 

 Lime. — Mr. George Hughes finds that this change 

 has taken place in deposits in the West Indian 

 islands of Berbuda and Aruba. In the latter case the 

 deposit occurs at a headland called Sierra Colorado, 



and Mr. Hughes is of opinion that this was formerly 

 the resort of sea-birds, whose excrement, which 

 contained soluble phosphates, caused the change in 

 the rock. 



Paramorphoses of Pyroxene into Ampiii- 

 bole.— From the paragraph in Science-Gossip for 

 March, it is refreshing to find that some of the British 

 scientists are taking up this subject practically ; as it 

 seems rather derogatory to British lithologists that 

 just as the Americans are casting aside their "fad" 

 about the old crystalline rocks, the former should 

 step into their old clothes. Mr. Harris Teall, how- 

 ever, can scarcely be said to be the first in the field, as 

 there are a few others before him, as mentioned in the 

 recently published paper by Professor G. H. Williams 

 of John Hopkins College, Baltimore ("American 

 Journal of Science "). Paramorphoses is the field to 

 which the microscopist ought to turn his attention, 

 as by it he learns what changes may and do take 

 place during metamorphosism, no matter what is the 

 age of the rocks. The changes to which the pyroxene 

 is subjected are those more easily seen ; but asso- 

 ciated with them are other changes, as of the felspars ; 

 the latter, however, seem to be, at least in part, 

 more methylatic than paramorphosic, as there appear 

 to be new minerals developed ; the change of a 

 triclinic into a uniclinic felspar being accompanied 

 by the development of accessory minerals. This 

 subject is, however, treacherous ground, as it seems 

 possible that it may be paramorphoses and not 

 methylosis that has been at work ; as the different 

 minerals that make up a triclinic felspar may be 

 developed and not actually chemically changed. 

 There are some peculiarities in connection with 

 pyroxenic rocks, often absent, but not always, in 

 felstones. Very commonly associated with a 

 pyroxenic rock, let it be as an "intende" or mass, 

 bedded, or as a dyke, there are schistose portions, 

 and the pyroxene in the latter changes much more 

 rapidly into hornblende, than the pyroxene in the 

 more solid portions ; also a pyroxenic tuff or tuffose 

 rock will change more rapidly than a compact rock. 

 Subsequently, however, there appears to be a change 

 in their relative sensibilities, as, during more excessive 

 metamorphic action, the compact rock may change 

 into a granyte, while the hornblendyte retains more 

 or less its schistose character. The ordinary changes 

 seem to be in the following order : — 1st, there is the 

 pyroxenic rock, in part tuffose, and in part compact ; 

 2nd, hornblendyte, and a rock in part pyroxenic and 

 in part amphibolic ; 3rd, hornblendyte and horn- 

 blendic gneiss ; 4th, gneissose hornblendic granyte, 

 having subordinate hornblendic schistose beds or 

 courses ; and 5th, metamorphic granyte ; the action 

 having become sufficiently intense to destroy the 

 individuality of the original rocks. — G. H. K. 



" Our Common British Fossils, and Where 

 to Find Them." By Dr. J. E. Taylor, F.G.S., 



