54 THE AMEEICAN MONTHLY [March, 



examined, many of the grahis may be seen in the act of discharging 

 their contents. I have never been able to ascertain exactly how far the 

 tube penetrates the stigma, but not more, I think, than a millimeter or 

 two. The protoplasm after leaving the pollen tube, by pressure from 

 behind and capillary attraction, passes rapidly to the ovary. It passes 

 out in a constant stream and takes about fifteen minutes to empty the 

 grain. — J, M. Barrow. 



Petrified Wood. — Dr. Sylvester's beautiful section of a rose stem, 

 showing the ducts so well, has prompted me to make a mount of a 

 coniferous or gymnospermous fossil wood ; in which order with the 

 peculiar medullary rays, and the pitted structure, the absence of all 

 ducts is characteristic. Fossil or petrified wood usually has to be 

 sliced by grinding in order to get a section for the microscope. Hap- 

 pily in this unique instance nature has furnished us with casts in pure 

 silica of every organism of the plant in absolute fac simile., and ex- 

 quisite sharpness of detail. Here there is no injurious flattening, as 

 occurs in a ground or sliced section. The pitted cell or structure stands 

 out in all its lenticular rotundity. In some parts of the slide these may 

 be seen shelled out, as peas from the pod, leaving a clean circular cav- 

 ity in which each had fitted. The medullary rays are also shown with 

 their smaller and somewhat elongate pitted markings, but nowhere is 

 any duct seen. The specimen is from a large piece of a fossil ti'ee 

 stem obtained in clipping at Asbury Park, N. J. It is a conifer, and I 

 should identify it as the fossil genus Cufresslnoxylon. I regard it as a 

 tertiary fossil, but there is doubt as to its exact geological position. 

 The plant is found fossil in Greenland as well as in New Jersey. Of 

 the Greenland flora, I only know of one plant that has survived in our 

 State, and that is a fern. — Samuel Lockwood. 



Diatoms from an Artesian ^A^ell. — The fossil marine diatoms on 

 this slide were found in the material taken from an artesian well at At- 

 lantic City during last year at the depth of 6io feet from the surface. 

 The diatom bed was found to be 300 feet in thickness, and it was 

 first reached at a depth of 400 feet from the surface. So that, estimat- 

 ing the great lapse of time required to form the deposit on the bottom 

 of the ocean at twenty years for each inch (which is considered a mod- 

 erate average of advance of time among naturalists), we then have 240 

 years for each foot and the enormous period of 72,000 years for the 

 total deposit of 300 feet; and then, in addition to the above period, it 

 will be necessary to approximate the time required to form the 400 feet 

 of non-diatomaceous material which overlies the 300 feet of fossil dia- 

 toms. — Henry JBerger. 



Diatoms. — Fresh-water diatoms from coherent but friable peaty ma- 

 terial, dark colored, with a grayish hue ; consisting of vegetable mat- 

 ter, sand, and diatoms, found at Northboro', Mass., lying directly 

 upon a glacial deposit and associated with the remains of a mastodon. 

 The original material came from Prof. F. W. Putnam, who gave the 

 above details of locality to Fred. K. LeRoy Sargent in 1886, from 

 whom the present contributor received it in 1889. 



Mr. C. Henry Kain, to whom I am indebted for a list of the species, 

 says the forms are those which are common in several places in New 

 England in peat formations, and also living in fresh water lakes and 

 streams, and that their chief interest is on account of their association 

 with the remains of the mastodon. — Chas. W. Swan., M. D. 



