12 



Nyl TURE 



[November 2, 1893 



hope that an interesting man who lived in a most interest- 

 ing period may yet find a biographer who will adequately 

 bring him into the light out of the shadow of the giants 

 who were in the earth in those days — Cromwell, Milton, 

 Newton, Spinoza, Boyle — in the midst of whom he 

 moved, and by whose great names his own has hitherto 

 been too much obscured. Herbert Rix. 



THE NATURAL HISTORY OF EAST 

 EQUATORIAL AFRICA. 



TR E geology of East Equatorial Africa has been re- 

 corded in a very general way in the maps of the 

 region published by Mr. Jos. Thomson in his " Through 

 Masai Land," and in the more recent one of Prof. 

 Toula ; from these it was known that the area consists 

 of a basal plateau of gneiss and schists, covered by a 

 series of lavas in the interior and marked along the 

 coast by patches of Jurassic rocks. My work therefore 

 lay in the main in the examination of the gneisses and 

 schists with a view to the determination of the method of 

 their formation ; also to the study of the volcanic rocks 

 — which range from basalts to quartz trachytes — and of 

 the relations of the old lava plateaus and sheets to the 

 craters of various ages which play such a striking part 

 in the scenery of the district. The most interesting part 

 of the work consisted in the examination of the great 

 " Graben " or valley of subsidence which runs north and 

 south across the district ; on the floor and on the sides of 

 this are many old lake deposits now buried by lava flows, 

 while the walls are also marked by terraces formed by 

 the existing lakes when at a higher level than at present, 

 or by old ones that have long since disappeared. In 

 some of these terraces are shells with Nilotic affinities, 

 though the localities are now far from the Nile basin. 

 The collections made from the coast Jurassics will al'ow 

 the age of these beds to be definitely settled, and the 

 fossils — Ajninofiitcs, Lytoceras, Bclcjiini/es, &c. — suggest 

 that they are probably Callovian. An interesting addi- 

 tion to the geology of tropical Africa has been the dis- 

 covery of some Palaeozoic shales, more than 130 miles 

 from Mombasa, which have yielded a fairly good fauna, 

 though richer in individuals than species. 



The evidence collected proves the existence of a 

 former race of men who used obsidian implements, and 

 who lived in a period long prior to any existing tribes ; 

 and also, that the glaciers on Mount Kenia once ex- 

 tended several thousand feet further down the mountain 

 than at piesent; in fact, a regular sheet or cap 

 glaciation preceded the existing valley glaciation. 



Zoologically the district is somewhat barren, and in 

 many parts only animals with great powers of migration 

 or hybernation are to be seen. In some of the country 

 most famous for its game, none can be found, as it was 

 killed off by last year's drought Cattle disease is respon- 

 sible for the disappearance of many species ; thus, 

 whereas buffalo used to be extremely common, only 

 three were seen ; only one herd of giraffes was met with. 

 Zebra and ostriches are abundant in places, while the 

 commonest antelopes seen were the hartebeest, mpalla, 

 and water buck ; topi are numerous on the Tana. 

 The sparseness of dense forest, except on the higher 

 parts of the district, accounts for the rarity of monkeys. 

 Colobics giierazi was seen at over 9000 feet on Kenia, 

 and some baboons amid the rocks of one of the ridges 

 of the basin of Lake Kibibl. Hyena and a small bush 

 buck range up into the lower Alpine zones on Kenia, 

 while a small rat, Hyrax, and elephants occur in the 

 woods of Sctiecio johnstoni in the upper Alpine zone. 

 Another high record is the occurrence of fresh water 

 crabs (Telephiisd) in some swamps on Leikipia at the 

 height of about 8000 feet. 



The rarity of limestones doubtless helps to the scarce- 



NO. 1253. VOL. 49] 



ness of mollusca. As is well known, most of the species 

 live on trees, whether in river valleys, such as the Sabaki, 

 or among the forests of Kenia, where some small delicate 

 species are common from Sooo to 10,000 feet. 



Botanically also, the country is somewhat barren and 

 monotonous ; vast areas are covered by nothing but 

 low, umbrella-shaped acacias. The country may be ■ 

 roughly divided into seven zones. The first includes the 

 coastal plain and river valleys, characterised by the 

 abundance of palms, such as the Dum palm {Hyphane 

 ihcbaica) and the Borassus palm {B. flabelliformis) ; the, 

 former is abundant along the coast and fringes the rivers, 

 being found up the Tana as far as south of Kenia, and 

 up the Sabaki to Tzavo. The Screw palm [Fandajius) 

 is rarer, but has a similar range. The salt marshes and 

 lagoons are bordered by the mangrove, while the she-oak, 

 or Casi/an'na, occurs on the ends of exposed promontories 

 on the coast. These have doubtless grown from cones 

 carried by currents from Australia, just as the Krakatab 

 pumice, which now forms banks along the shore, has 

 floated from Malaysia. This zone is succeeded by great 

 sandy steppes covered with mimosa and acacia scrub, 

 with large baobabs, which occur also on the coast. The 

 most typical plants have large and white flowers, a species 

 of Convohndus being the commonest Aloes, and es- 

 pecially the species known to the Suahili as " nkonge," 

 are abundant. The two next zones are the steppes and 

 woods of the high plateaus ; the most striking feature of 

 the former is the high grass, which, when the seeds are 

 ripe and yellow, reminds one of the great cornfields of 

 Dakota. 



In places the forests of the plateaus pass upward 

 gradually into those of the flanks of the higher mountains, 

 such as Kenia and Settima. The prevalence of lofty 

 junipers which replace the trees of lower horizons, and 

 the dense jungles of bamboos, with a carpet of Selaginclhx 

 characterise the fifth or bamboo zone. 



Above this are the Alpine pasturages. In the lower 

 part there are numerous orchids. Gladiolus, &c. With 

 the upper zone there appear species of the " everlasting 

 plants" of the Cape, while the only trees are Scnecio 

 joluistoni. Beyond this is the zone above the snow line, 

 where except for a few diminutive yellow composites 

 and lichens, we have passed beyond the realms of plant 

 or animal life. J. W. GREGORY. 



NOTES. 

 Dr. Potain has been elected a member of the Paris Academy 

 of Sciences (Section of Medicine and Surgery), in the place of 

 the late Prof. Charcot. 



We are sorry to learn of the death of Dr. H. H. Ashdown, on 

 October 10, at the age of thirty-four. He was a Fellow ot 

 the Royal Society of Edinburgh, and published several memoirs 

 on his physiological investigations. 



We regret to announce that Mr. T. C. Bain, the Government 

 surveyor and geologist at the Cape, died at Rondebosch, Cape 

 Town, on Ssptember 28. He was born in 1830, and his 

 father was ihe engineer of the well-known Mitchell's Pass Road, 

 at Cape Colony. Mr. Bain was appointed irrigation and 

 geological surveyor in 18S8. The British (Natural History) and 

 Cape Museums contain a number of geological specimens 

 collected by him, among which may be mentioned the collection 

 of reptilian remains from the lacustrine beds of the Karoo. 



A State Museum is now in course of formation at Pretoria. 

 Mr. P. Krantz has been appointed a curator, and he has, with 

 an entomological assistant, just started on a collecting expedi- 

 tion, which may probably occupy a space of two years. Their 

 mode of transit is in a large wagon drawn by twenty donkeys, 

 these animals having been chosen as best able to withstand the 



