January 13, 1888.] 



SCIENCE. 



21 



obtained now, the laboratory will be opened next summer. The 

 following is a list of the lecturers and their subjects : Jan. i8, Prof. 

 W. H. Niles of the Massachusetts Institute of Technology, ' Moun- 

 tain Sculpture ; ' Jan. 25, Maj. J. W. Powell, director of the United 

 States Geological Survey, ' Savagery, Barbarism, and Civilization ; ' 

 Feb. I, Prof. H. N. Martin of the Johns Hopkins University, ' A 

 Hen's Egg ; ' Feb. 8, Prof. George L. Goodale of Harvard College, 

 'Seeds;' Feb. 15, Prof. F. W. Putnam, director of the Peabody 

 Museum of American Archjeology and Ethnology, at Cambridge, 

 ' The Serpent Mound and the Ancient People of the Ohio Valley ; ' 

 Feb. 22, Prof. Alpheus Hyatt, curator of the Boston Society of 

 Natural History, ' A practical Example of the Evidence for Evolu- 

 tion ; ' Feb. 29, Dr. Henry P. Bowditch, dean of the Harvard Medi- 

 cal School (subject to be announced) ; March 7, Prof. Edward S. 

 Morse, director of the Peabody Academy of Science, Salem, ' Rep- 

 tilian Affinities of Mammals.' 



LETTERS TO THE EDITOR. 



■ble. Tlie 



ation will be fitrnished 

 t with the character of 



*»* Corresfiondents are requested to be as brief a^ 

 in allcases required as proof of £rood faith. 



Twenty cofiies of the number containing his ci 

 free to any correspondent on request. 



The editor will be glad to publish any queries 

 the journal. 



The Trinity Formation of Arkansas, Indian Territory, 

 and Texas. 



During the past field-season the writer has had an opportunity 

 to study the small mesozoic area in the south-west corner of the 

 State of Arkansas and south-eastern Indian Territory, which is the 

 north-eastern termination of the great area so well developed to the 

 southward in Texas. By courtesy of Dr. John C. Branner, State 

 geologist, I am permitted to publish the following note in advance 

 of the more detailed official report which will soon be published by 

 him. 



In previous papers {American Naturalist, Feb. 1887 ; American 

 loiirfial of Science, April and October, 1887) I have shown that 

 the mesozoic strata of the Texas region, instead of belonging to the 

 uppermost cretaceous as had been previously supposed, really em- 

 braced a large series of lower cretaceous and perhaps Jurassic beds. 

 To the last-named period I intimated that the strata in Parker 

 County, Tex., provisionally termed in my section the ' Dinosaur 

 Sands," would probably be found to be related. The studies of the 

 past season in Arkansas have shown that these strata exhibit great 

 uniformity of deposition along the paleozoic and mesozoic parting 

 from south of the Brazos River in Texas, to the Little Missouri 

 River near Antoine, Pike County, Ark., a distance of over three 

 hundred miles, and that they rest directly upon the highly disturbed 

 carboniferous rocks. In Texas the areal extent of this formation 

 coincides with the eastern half of the Upper Cross Timbers, and in 

 Arkansas it extends from the point above mentioned westward to 

 beyond Ultima Thule. Its width, except for a few miles on each 

 side of Red River, never exceeds a few miles. The formation 

 consists of alternations of fine, closely packed white sands and red 

 and blue gypsiferous marls, with occasional alternations of thin but 

 extensive, fissile, arenaceous, and crystalline limestones, highly fos- 

 siliferous, often wave-marked, and seldom more than ten inches in 

 thickness. Extensive strata of pure saccharoidal gypsum also occur 

 in places, and the formation is the source of the salines and salt 

 licks throughout its extent, and probably also of the ' brackishness ' 

 of the rivers which intersect it. 



This formation is clearly distinguished from the overlying creta- 

 ceous (which deposits are later and later as we proceed eastward 

 along the contact) and the underlying carboniferous. West of 

 Weatherford the basal Comanche series may be seen resting di- 

 rectly upon it, while, at the point of its disappearance under the 

 newer strata in Arkansas, it is directly covered by the uppermost 

 cretaceous of Hilgard's Mississippi section. 



The fauna of this formation is littoral and of great uniformity 

 throughout its extent, and, upon hasty observation, conveys an im- 

 pression that it is later than it really is. It consists of characteris- 

 tic molluscan species which are hardly distinguishable from certain 

 characteristic European forms specially indicative of the Upper 

 Jurassic and Wealdan. I hope to give more detail concerning these 



fossils in a special paper hereafter. In Texas I found what are at 

 present supposed to be dinosaurian remains ; and occasional veg- 

 etal remains are met with. 



To the •continuous formation the name of 'Trinity' is applied, 

 from the rivers of that name which arise in it. This includes the 

 strata which I termed ' Dinosaur Sands ' in my Texas section. 



The discovery of these trans-Mississippi beds of Jurassic affini- 

 ties is of importance, in that it indicates a close relation and pos- 

 sible continuity between the pre-cretaceous mesozoics of Colorado 

 and the Texas Pan-handle, and the Tuscaloosa and Potomac beds 

 of the cis-Mississippi region. Rob't T. Hill. 



U. S. Geol. Surv., Washington, D.C., Jan. 6. 



Children's Development. 



Recently I became interested in the vocabulary of my boy, 

 thirty months old, and for one day noted all words used by him, ex- 

 cept proper names. No effort was made to exhaust the child's 

 stock of words by questioning. He used three hundred and fifty- 

 two words, of which fifty-four per cent were nouns, eighteen per 

 cent verbs, and eleven adjectives. It is probable that the child's 

 entire vocabulary of dictionary words includes four hundred or 

 more. G. 



Washington, D.C., Jan. 4. 



Is there a Venomous Lizard (Heloderma)? 



This animal has been an object of considerable interest to nat- 

 uralists because of the question whether or not it presents the 

 anomaly of a venomous lizard. Just before leaving the United 

 States, last September, I had under my care about twenty so-called 

 ' venomous lizards ' of various ages and sizes ; and, as I believe the 

 biography of this animal has been but slightly touched on, a few 

 observations in regard to them may not be out of place. 



They varied in length from 19 to 49.5 centimetres. The larger 

 ones, say above 43 centimetres, were all females. Their colors 

 ranged from almost a brick-red to pale pinkish white, with mark- 

 ings from black to Vandyke brown, which showed no regularity in de- 

 tails, appearing as if each lizard had been the subject of some Chinese 

 artist who aimed only at the general effect. They all came to my 

 father's establishment, in Rochester, by express ; and the shaking- 

 up and lack of freedom that they had undergone served to make 

 them very irritable. When first liberated from their confining 

 boxes, their first desire was to get hold of the nearest person, and, 

 although usually very sluggish, they would then move with surpris- 

 ing agility, turning end for end, and making short dashes hither and 

 thither with great swiftness. When one succeeded in fastening its 

 teeth in my clothes, it held on with the tenacity of a bull-dog, 

 occasionally giving a vicious shake to its head, as if trying to tear 

 away a piece of the cloth. Nor was this pugnacity confined alone to 

 the time of their arrival, but continued in lesser degrees during the 

 entire time that I had them under observation. Once I saw a 

 pitched battle between two. One had its teeth firmly fixed in the 

 throat of the other, who, in turn, had a leg of the first in its jaws. 

 Together they rolled and twisted over the floor, neither relaxing its 

 hold for a period of fifteen minutes. Blood was drawn on both 

 sides, yet neither afterwards appeared the worse for the conflict. I 

 then tried two of them on a hen, to ascertain if they would prove 

 poisonous to her. Having first shaved the thigh of the hen, so that 

 the feathers might not interfere wth the entrance of any poison, I 

 induced one of the lizards to take hold. This it readily did, and 

 retained its grip for five minutes, occasionally shaking its head in 

 a savage manner. During the operation the hen appeared quite 

 impassive, and, although not tied, made no attempts to escape, 

 evidently charmed by the lizard. A little blood was drawn, show- 

 ing that the flesh had been thoroughly pierced. For perhaps a 

 half-hour afterwards the hen appeared a trifle stupid, but soon re- 

 gained its normal condition, and gave no signs at all of poisoning. 

 Two days later I repeated the experiment with another lizard, with 

 a similar lack of results. I then caused one of them to bite the 

 edge of a saucer, and, with a hypodermic syringe, injected the fluid 

 obtained in the breast of a pigeon. No effect. Then, exciting one 

 so that it viciously bit a small piece of wood, I drew a considerable 

 quantity of fluid direct from its mouth, which, injected into the 

 pigeon's breast, produced no results. 



