January io, 1890.] 



SCIENCE. 



3r 



eastern slope, doing but little damage, however, as it was some 

 distance from the town on that side. The ashes injured the crops 

 on the eastern slope, and also those about Rivas. Smoke con- 

 tinued about three years in interrupted emissions, with violent 

 rumbling, but no trembling of the earth. Like Monotombo, it is 

 out of the axial line of the older and extinct volcanoes which lie 

 between them and the primitive Cordilleras. If a line be drawn 

 from Omotepe to Tipitapa, and thence to Cosequina, including 

 Monotombo, the volcanic region of this district, in remote and 

 recent times, is included within it. 



This volcanic district referred to was the first occupied by early 

 man, and even at the present time it is the most thickly populated. 

 Strange to say, those who have written about this portion of Ni- 

 caragua, either in a historical or scientific sense, have entirely 

 ignored it. Especially is this true in regard to its geology. Know- 

 ing this to be true, I requested Mr. I. Crawford, who is in the em- 

 ploy of the government, to give me his views in regard to the 

 geological formation of this state. His remarks upon the subject 

 are as follows. 



" Geology, in the larger part of Nicaragua, promises many in- 

 teresting and valuable revelations to scientists searching for evi- 

 dences of time and life. It is generally supposed by the world at 

 large, that Nicaraguans are rocked to sleep by earthquakes, but 

 you know that this is a mistake. So far, I have not been obliged 

 to tread in the footprints of scientific predecessors. The geology 

 and mineralogy of this region has never- been studied before. 

 Organic matter in this country is not a kind of infusoria from active 

 and extinct volcanoes ; neither has all the organic matter in Ni- 

 caragua been incubated in the yet warm craters of extinct, nor 

 singed by hot eruptions from active, volcanoes. Having been 

 ordered by the commissioners of Granada to make a typical collec- 

 tion for exhibition at Paris, I was obliged to hurry over the moun- 

 tains and ravines of this country in order to accomplish the work 

 in time for shipment to France. The collection of geological and 

 mineralogical specimens that I formed demonstrates that Nicara- 

 gua is not the volcanic region that Spanish gold-hunting and 

 Indian-murdering priests declared it to be. This mistake has 

 been copied so frequently by careless investigators that at present 

 it passes unquestioned by our great European and America scien- 

 tific associations. It is well known, that, so far, there never has 

 been even a superficialexamination of the geology and mineralogy 

 of the region we speak of. Levy's history of Nicaragua contains 

 so many evidences of its unreliability, that any person upon read- 

 ing it is impressed at once with the fact that Levy is not relating 

 what he saw, or obtained from reliable sources, in regard to the 

 geology of this country : he is simply drawing upon his imagina- 

 tion. What a sad example for members of scientific associations 

 who hurry into print, copying and publishing as facts things that 

 they have not investigated, thus perplexing hardworking searchers 

 for truth. I quote here the following paragraphs from one of my 

 recent reports to the government of Nicaragua. ' On account of 

 diversity in the geological formations, and for the sake of easy 

 reference, I divide this country (Nicaragua) into three parts, called 

 eastern, central, and western. The eastern is bounded on its 

 south-western part as follows ; commencing at 87° west longitude, 

 from Greenwich, and 30'^ 30' north latitude, and extending by an 

 irregular line to 85° 50" west longitude, and 12° 45" north latitude, 

 thence to 85° 9" west longitude, and ix° north latitude. The 

 geological formation of the eastern division in the northern part is 

 composed of eozoic and lower Silurian rocks, minerals, and metals ; 

 some merely horizontal, others at various angles of inclination. 

 The Silurian, which rests unconformably on the eozoic, is in places 

 covered by alluvium formations. The middle and south-western 

 parts of this eastern division are eozoic-Silurian and in some cases 

 Devonian, each of the eras, in various places, well defined, but in that 

 undisturbed condition in which the primitive upheaval and subse- 

 quent contractions left them, resting at various angles of inclination. 

 No evidence of earthquakes, no volcanoes, no volcanic craters, are 

 to be found in any part of this eastern division.' We call particu- 

 lar attention to this fact, and have been so much occupied by field 

 work, in the mountains and ravines, that it has been impossible to 

 publish a detailed account of it. The specimens collected will, 

 however, keep fresh and tell the true story. In reference to glacia- 



tion, and moraines deposited by the glaciers, I found on the mesas 

 near Metapa, at Totumbli, rocks and moraines deposited by the 

 glaciers, and traced them toward the Pacific Ocean. 



" North-eastward for about 7 leagues there is an elevated plain 

 adjoining that part of the valley of Sebaco, in which, at the Rio 

 Viejo, I found a large deposit of petrified bones of quaternary and 

 tertiary animals. In my necessarily hurried examination of the 

 deposit where the bones were found, I recognized no bones of the 

 human body, but several bones of parts of the head.' There were 

 also a few teeth of large marsupials. These unexpected discover- 

 ies in this hitherto supposed hotbed for volcanoes I have not yet 

 carefully examined, but hope that time will soon be given for its 

 future study. Particular attention is called to these peculiarities in 

 the geological formation of this part of Nicaragua, which are not 

 in harmony with, but opposed to, statements and maps of all his- 

 torians about the geology and mineralogy of Nicaragua. I was 

 too much hurried in my examinations to satisfy myself as to 

 whether the bones were older, or were deposited, or which were 

 the older formation, they or the glacier. The nearest moraines 

 and glacier-marked rocks that I noticed were about two leagues 

 distant, 200 feet higher than where the bones are. The glacier 

 rocks may have been strewn over the valley on a surface deposit 

 of 200 feet directly over the bones, or, as the valley was — I have 

 some reason to believe — once much deeper than at present, most 

 probably the moraines and glacier-marked rocks falling in the 

 valley were washed down the Rio Viejo by large floods into the 

 present Lake Managua, and therefore the deposit of bones would 

 have been made subsequent to the glacier period." 



A word about the glacial period and its relation to the fossil 

 remains mentioned in the extracts of parts of Mr. Crawford's let- 

 ter as occurring in the cuttings of the Rio Viejo and the great plain 

 of Sebaco, emptying into Lake Managua, and his uncertainty about 

 them. As they occur some 200 feet lower than the moraines to the 

 north-east, requiring another visit to arrive at the truth, we must 

 say that those on the large stretches of lowland, north of Lake 

 Nicaragua, occur under like circumstances. These plains extend 

 back to the base of the old Cordilleras. Their upper surface is 

 composed of black alluvium lying along the northern bowlders, 

 which were the make-up of an inland sea, or ocean inlet, shut in 

 by the upheaval, after which the waters flowed back to the foot- 

 hills, from, or due to, an accumulation of rainfalls washing down 

 the alluvium. On the plain mentioned, north of the lake, were 

 found the bones of what Professor Baird said belonged to Elephas 

 primogenitas; while in the river banks to the east, formed of con- 

 glomerate detritus, stratified, and volcanic material (shown by 

 pebbles of scoria, worn smooth), laborers, while excavating there 

 in 1874, encountered a fossil human skeleton, some twenty feet be- 

 low the surface. 



Clear demarcations of geological epochs are found in this locali- 

 ty ; and the question of ice age here will be decided in the near 

 future so clearly that scientists will feel satisfied. It may be inter- 

 esting also to mentidn, that, in 1S63, while passing from Tipitapa 

 to Talolinga, I noticed glacial deposits ; also, on a hill back of San 

 Carlos, sharp fragments of quartz rock of large dimensions are of 

 glacial deposition. I called the attention of Professors Henry and 

 Baird to these facts years ago, and requested the geologist of the 

 first canal survey to visit the localities named, but he could not do 

 so on account of press of work. In a letter to the American Anti- 

 gtiarian I asserted that the fossils mentioned were above the clay 

 formation," under the ash-eruption that covered the vegetatior^ 

 whose fossil leaves may determine the geological period of Nicara- 

 gua, or the time of its disappearance. The coincidence of the fos- 

 sil leaves with those in the sedimentary rocks formed here after the 

 uplifted coast range, produced by the cataclysm, goes to show that 

 the glacial age here was disappearing. Near by, to the north-east, 

 the glaciers crowded on towards the fierce fires from the summits 

 of the old Cordilleras, trying to assert a supremacy in that conflict 

 of elements, both vieing in their work of desolation. The eternal 



* A distinction between the bones of the human body and head is evidently here 

 intended by Mr. Crawford and Dr. Flint. — H. T. Cresson. 



^ The ash-eruption did not extend north of the lakes to where the bones occur 

 It was an epoch of repose, of long duration, during which the accumulation of allu-. 

 vium was deposited around the lakes and over the glacial deposits in the location 

 mentioned. 



