420 MESOZOIC FLORAS OF UNITED STATES. 



scars of varying sizes, but all smaller than those last described. Only 

 one-half of this crow's nest is preserved, the other half, including a very 

 little of the terminal Inid, being eroded away, leaving a deep cavity, the 

 sides of which show no structure. The specimen is of a dark-reddish 

 coloi-. well silicified, and heavy. It stands 43 cm. high, is 35 cm. in the 

 major axis of a cross section at the largest pai't, some 15 cm. above the 

 base, and 2G cm. in its minor axis. The girth at the same point is 98 

 cm., while at the summit just below the break it is 86 cm. 



The peculiar vertical seam or broad mark seen on the side of this view, 

 and still better in the views published in Professor Fontaine's monograph, 

 pi. clxxix, clxxx, deserve special notice. It was described by Professor 

 Fontaine on p. 191 of the text of his monograph as "a projecting seam 

 of ferruginous silica. This is shown on the narrower side of the trunk 

 on pi. clxxx, and less distinctly on the front left-hand side on pi. clxxix. 

 This seam appears to be due to a crack in the trunk, which was filled with 

 infiltrated silica in the form of a vein. This silica in the projecting plate 

 or vein seems to be in part at least due to a partial filling of the crack by 

 sand, for grains of sand are mixed with the silica deposited from solution." 



On January 9 and 10, 1895, I described all the specimens then known 

 to be at the Johns Hopkins University geological museimi, including this 

 one, and wrote out my descriptions in full. In dealing with this feature 

 I found myself unable to agree with the interpretation of Professor 

 Fontaine. The following are my description and conclusions, as then 

 and there recorded, from which I have not since seen any reason to recede : 



The jjeculiar and conspicuous line that encircles this specimen from top to 

 bottom and is seen in all the ])liotographs is not due, as Professor Fontaine supposed, 

 "to a crack in the trunk, which was lilled with infiltrated silica in the form of a vein," 

 but is wholly superficial. It consists of a mainly dark ferruginous coarse sand 

 approaching gravel and thickly studded with larger white grains, mainly of worn 

 vein quartz, often small pebbles, and all firmly cemented. It has a width of a 

 little over half an inch and can be traced continuously around the specimen, very 

 distinct on both sides, less so where it traverses the base and summit. It fills all 

 the leaf scars and other depressions and appears in the form of a vein or dike uniform 

 with the extreme outer surface. But in most cases where it is crossed by the ramen- 

 tum walls these are seen perfectly intact passing through it. It does not pass round 

 the center of the specimen but much to one side, like a milky way, so that should 

 the trunk be split along that plane most of the axis would be in one of the parts. 



