30 REPORT— 1886. 



from stones taken up by the hooks of fishermen on the banks of New- 

 foundland, that rocky material from the north is dropped on these banks 

 by the heavy ice which drifts over them every spring, that these stones 

 are glaciated, and that after they fall to the bottom sand is drifted over them 

 with sufficient velocity to polish the stones and to erode the shelly cover- 

 ings of Arctic animals attached to them.' If then the Atlantic basin 

 were upheaved into land we should see beds of sand, gravel, and boulders 

 with clay flats and layers of marl and limestone. According to the 

 Challenger Reports, in the Antarctic seas S. of 64° there is 1 lue mud with 

 fragments of rock in depths of 1,200 to 2,000 fathoms. The stones, some 

 of them glaciated, were granite, diorite, amphibolite, mica schist, gneiss, 

 and quartzite. This deposit ceases and gives place to Globigerina ooze 

 and red clay at 46° to 47° S., but even further north there is sometimes as 

 much as 49 per cent, of cr3^stalline sand. In the Labrador current a 

 block of syenite weighing 490 lbs. was taken up from 1,340 fathoms, and 

 in the Arctic current 100 miles from land was a stony deposit, some stones 

 being glaciated. Among these were smoky quartz, quartzite, limestone, 

 dolomite, mica schist, and serpentine ; also particles of monoclinic and 

 triclinic felspar, hornblende, augite, magnetite, mica, and glaucorite, the 

 latter no doubt formed in the sea-bottom, the others drifted from i^i^ozoic 

 and Paleeozoic formations to the north.' 



A remarkable fact in this connection is that the great depths of the 

 6ea are as impassable to the majority of marine animals as the land itself. 

 According to Murray, while twelve of the OlialUnger's dredgings taken 

 in depths greater than 2,000 fathoms gave 92 species, mostly new to 

 science, a similar number of dredgings in shallower water near the land 

 gave no less than 1,000 species. Hence arises another apparent paradox 

 relating to the distribution of organic beings. While at first sight it 

 might seem that the chances of wide distribution are exceptionally great 

 for marine species, this is not so. Except in the case of those which 

 enjoy a period of free locomotion when young, or are floating and pelagic, 

 the deep ocean sets bounds to their migrations. On the other hand the 

 spores of cryptogamic plants may be carried for vast distances by the 

 wind, and the growth of volcanic islands may effect connections which, 

 though only temporary, may afford opportunity for land animals and 

 plants to pass over. 



With reference to the transmission of living beings across the Atlantic, 

 we have before us the remarkable fact that from the Cambrian age on- 

 wards there were on the two sides of the ocean many species of inverte- 

 brate animals which were either identical or so closely allied as to be 

 possibly varietal forms .^ In like manner the early plants of the Upper 

 Silurian, Devonian, and Carboniferous present many identical species ; but 



' Notes on Post-PUooene of Canada, 1872. 

 ' Oeneral Report, ' Challenger ' Expedition. 



* See Davidson's Monographt on Braohiopodt; 'EXhetidige, Address to Oeologiaal 

 Society of London, Woodward, Address to Qeologisti Association, also Barrande's Special 



