262 REPORT OF NATIONAL MUSEUM, 1899. 



journey, leidh.) The Icelandic government in that j^ear bought a quarter 

 share of the quarry, and stopped the work, so that Tulinius was glad 

 to sell them the rest. Five years ago an attempt was made to reopen 

 it. One man was employed, and after spending about a week in the 

 cave he succeeded in pumping out the water and extracting a fine 

 block of clear spar, which was sold at a high price in London. Here, 

 however, the work dropped, and in consequence Tulinius remains the 

 proprietor of the whole of the calc spar that is available for physical 

 work, and naturally sells it at a price that is calculated to make his 

 very moderate stock last for a considerable time.^ The reason of the 

 Icelandic government is not very clear, but as the working of the quarry 

 is, perhaps from patriotic motives, delegated to Herr Gunnarsson, an 

 Icelandic merchant, whose nearest warehouse is at Seydhisfjordhr, a 

 good day's ride from Eskifjordhr, it is hardly to be expected that the 

 buried treasure will soon see the light. Perhaps, too, the specimens 

 of the best quality have been already removed. Certainly clear pieces 

 do not constitute the great mass of the spar, and if M. Labonne, who 

 visited the cave in May, 1877 (the water being at that time frozen), 

 could extract it " en assez grande abondance"^ he did not leave much 

 exposed for me to take two years later. M. Labonne speaks in his 

 note of ramifications into the environing rock which have never been 

 worked and suggests that this investigation might increase the impor- 

 tance of the quarry. Such ramifications as I could see were on a very 

 small scale. On the other hand, the thickness of the deposit has not 

 yet been ascertained, but it is said that the best pieces occurred near 

 the surface. For the most part the calcite is rendered semiopaque by 

 innumerable cracks, generally following the gliding and cleavage planes 

 ( — i K and R), and apparently produced by the pressure of the spar 

 itself, but sometimes following the conchoidal fracture. Remarkable 

 examples of the latter kind are in the British Museum. 



Chalk. — This is the name given to a white, somewhat loosely coherent 

 variety of limestone composed of the fineh' comminuted shells of marine 

 mollusks, among which microscopic forms known as foraminifera are 

 aVjundant. The older text-books gave one to understand that f oraminif- 

 eral remains constituted the main mass of the rock, but the researches 

 of Sorby'' showed that fully one-half the material was finely com- 

 minuted shallow-water forms, such as inoceramus, pecten, ostrea, 

 sponge spicules, and echinoderms. 



Chalk belongs to the Cretaceous era, occurring in l)eds of varying 

 thickness, alternating with shales, sands, and clays, and often including 

 numerous nodules of a dark chalcedonic silica to which the name 



' It is sold ])y Thor E. Tulinius, Slotsholnisji'ade 10, CVjpenhageii K. 



^Comptes Rendus, CV., 1887, p. 1144. 



^ Address to Geological Society of London, February, 1879. 



