6io 



NA TURE 



[April 27, 1893 



masses of seolian rocks which had been thrown up along 

 the slope of the cay about 80 feet from high-water mark 

 to a height of 20 feet. One of these masses was 15' 6" x 

 Ii"x6'. We then kept on to Great Stirrup Cay coasting 

 along the Berry Cays, crossed over to Morgan's Bluff, on 

 eastward of Andros down to Mastic Point on the same 

 Sound, and then returned to Nassau. 



The islands of the Bahamas (as far as Turks Island) 

 are all of seolian origin. They were formed at a time 

 when the Banks up to the lo-fathom line must have been 

 practically one huge irregularly shaped mass of low land, 

 from the beaches of which successive ranges of low hills, 

 such as we still find in New Providence, must have 

 originated. After the islands were thus raised there was 

 an extensive gradual subsidence which can be estimated 

 at about 300 feet, and during this subsidence the sea has 

 little by little eaten away the asolian lands, leaving only 

 here and there narrow strips of land in the shape of the 

 present islands. Inagua and Little Inagua are still in 

 the original condition in which I imagine such banks as 

 the Crooked Island Banks, Caicos Banks, and other 

 parts of the Bahamas to have been ; while the process 

 of disintegration going on at the western side of Andros 

 shows still a broad island which will in time leave only 

 the narrow eastern strip of higher land (aeolian hills) on 

 the western edge of the tongue of the ocean. Such is 

 the structure also of Salt Cay Bank which owes its pre- 

 sent shape to the same conditions as those which have 

 given the Bahamas their present configuration. My 

 reason for assigning a subsidence of 300 feet is the depth 

 of some of the deep holes which have been surveyed on 

 the bank and which I take to be submarine blow-holes 

 or caverns formed in the aeolian limestone of the Bahama 

 hills when they were at a greater elevation than now. 

 This subsidence explains satisfactorily the cause of the 

 present configuration of the Bahamas, but teaches us 

 nothing in regard to the substratum upon which the 

 Bahamas were built. The present reefs form indeed but 

 an insignificant part of the topography of the islands 

 and have taken only a secondary part in filling here and 

 there a bight or a cove with more modern reef rock, 

 thrown up against the shores so as to form a coral reef 

 beach such as we find in the Florida Reef. I have 

 steamed now nearly 3300 miles among the Bahamas, 

 visiting all the more important points and have made an 

 extensive collection of the rocks of the group. 



I hoped to have made also a larger number of deep 

 soundings than I have been able to take ; unfortunately 

 the trades were unusually heavy during the greater part 

 of my visit to the Bahamas, greatly interfering with such 

 work on a vessel no larger than the Wild Duck — 127 feet 

 on the water line. For the same reason the number of 

 deep-water pelagic hauls was also much smaller than I 

 hoped to make, as in a heavy sea the apparatus would 

 have been greatly endangered. It is a very different 

 thing to work at sea in a small yacht like the Wild Duck 

 or in such vessels as the Blake and the Albatross of large 

 size and fitted up with every possible requirement for 

 deep sea work. The Wild Duck, on the other hand, was 

 admirably adapted for cruising on the Bahama Banks, 

 her light draught enabling her to go to every point of 

 interest and to cross and recross the banks where a larger 

 vessel could not follow. I am under the greatest obliga- 

 tions to my friend Mr. John M. Forbes for having so 

 kindly placed his yacht at my disposal for this explora- 

 tion, and I hope soon after my return to Cambridge to 

 publish more in detail the results of this examination of 

 the structure of the Bahamas. 



ARTIONYX—A CLAWED ARTIODACTYLE. 

 T F any further evidence were needed to disprove 

 ■'■ Cuvier's famous generalisation, it is found in the 

 recently discovered hind foot of Artionyx. In this foot 



NO. 1226, VOL. 47] 



each of the digits with all the phalanges are modified very 

 much as in the primitive bears, and combined with 

 metatarsals and an ankle joint almost identical with those 

 of the pigs. The termination of the limb in claws would 

 have led Cuvier to predict that the whole skeleton and 

 the dentition was of a clawed or carnivorous type, 

 whereas in this animal we find the foot alone belongs to 

 two types as widely separated as can be, and the pro- 

 babilities are that the skeleton and teeth are also mixed 

 in character. 



The foot of Artionyx was found last summer by the 

 American Museum party under Dr. Wortman, in the 

 same beds with the remarkable Protoceras recently 

 described in Nature. It belonged to an animal about 

 the size of a peccary. The terminal claws were first 

 exposed, and although found uncleft, they at once sug- 

 gested a reference to Chalicotherium, for which the 

 party was keeping a sharp look-out ; but a further re- 

 moval of the matrix showed a pes of an entirely distinct 

 character. In the foot of Chalicotherium magnum of the 

 Upper Miocene of France we find three toes, thus odd 

 in number, but not strictly perissodactyle, for the largest is 



c. External. 

 Right hind foot of A rtionyx gaudryi. 



not the median but the outer toe. Above the toes is an 

 ankle joint of a modified perissodactyle type, that is, the 

 astragalus is grooved upon its tibial side, and flattened 

 where it rests upon the navicular. The navicular and 

 cuneiforms are also flattened, so that the foot must have 

 been placed somewhat at an angle with the leg, as it is 

 in the Sloths. In Artionyx, on the other hand, there are 

 five digits ; the first, or thumb, was a dew-claw, very 

 much shorter than the rest ; the remaining four, as shown 

 in b of the figure, are nearly symmetrically placed in 

 pairs on either side of the median line, precisely as in 

 the Artiodactyla. This has suggested the name of the 

 animal, its even-numbered toes terminating in claws. 

 Above these elements we have a coalescence of the outer 

 and middle cuneiforms as in many Artiodactyla. The 

 cuboid, navicular, astragalus, and calcaneum, are also 

 modified precisely as in the artiodactyles. The fibula 

 comes down upon the heel bone, and there is the charac- 

 teristic double hinge. The tibia is strongly interlocked 

 on the outer side of the astragalus. The three accom- 

 panying cuts exhibit the peculiar features of this foot ; 

 the side views showing that the animal was digitigrade 

 like the cats, and not plantigrade like the bears, although 

 the claws were more of the bear than the cat type. 



