432 



NATURE 



{March 28, 1878 



Management likewise determined that the cost of the 

 Annual Reports should in future be paid out of the yearly 

 appropriation, thereby of course, considerably narrowing 

 the possible amount of work to he done in the field. In 

 spite of these drawbacks, however, the State-geologist 

 succeeded, during his first year of office, in doing some 

 useful work, and yet kept a sufficient balance to publish a 

 bulky report with a quarto atlas of plates. His plan was 

 to attack first of all those branches of inquiry which pre- 

 sented the greatest interest or had the closest bearing upon 

 the industrial resource? of the State. The ground was sur- 

 veyed by counties, Mr. Broadhead himself taking a lion's 

 share of the hard work. The two lead regions of South- 

 west and Central Missouri were likewise examined. Many 

 analyses were also made of the ores, slags, coals, and 

 other mineral substances sent up to the office. The 

 Report which gave an account of these labours cannot 

 fail to be of great service in the development of the 

 mineral resources of the State. Mr. Broadhead is evi- 

 dently exactly the kind of director needed to keep the 

 Missouri Geological Survey in full activity and to satisfy 

 the demands of a utilitarian legislature. 



The oldest rocks in Missouri appear to be certain 

 granites and other crystalline masses, on which lie some- 

 where about 3,000 feet of Lower Silurian strata, including 

 representatives of the Potsdam, Black River, Birdseye, 

 Trenton, and Cincinnati groups of other parts of the 

 United States. Upper Silurian rocks are much more 

 feebly represented, but Dr. Shumard has recognised beds 

 probably equivalent to the lower Helderberg and Niagara 

 groups. The Devonian groups of Hamilton and Onon- 

 dago are still more sparingly developed, only about 100 

 feet of strata being referable to those horizons. The Car- 

 boniferous system, however, is well displayed, and contains 

 the following groups : — 



Lower 



Uppbr. 



\ 



Upper coal-measures (poor in coal) 1,307 feet. 



Middle ,, (with 7 ft. of coal) 324 „ 



Lower ,, {with 13 ft. 6 in. of coal) ... sso-300 ,, 



'Chester group (sandstone) from a few feet to ... 100 „ 



St. Louis ,, (limestone), maximum 



Keokuk „ (shale and chert), perhaps exceeding 



Encrinital or Burlington group 



Chouteau limestone 



Vermicular sandstone and shales 



^ Lithographic limestone 



250 

 300 

 60 



ICO 



75 

 55 



No later formations occur until we reach the " Drift. 

 This consists of two divisions ; the lower, formed of dark 

 blue clay, overlaid and interstratified with beds and 

 pockets of sand sometimes inclosing remains of terres- 

 trial vegetation ; the upper composed of stiff", tenacious, 

 brown, drab, and blue clays, often mottled, and contain- 

 ing rounded granitic pebbles. Large boulders of crystal- 

 line rocks from a northern source occur in the lower 

 division, up even to a height of 1,050 feet above the level 

 of the C^ulf of Mexico. Most of the observed boulders 

 occur in the valleys. They diminish in numbers and size 

 as they are traced southwards, the Missouri River seem- 

 ing to limit their extension in that direction. Above 

 these clays lies the " bluff," or loess, a very fine light 

 brown siliceous mar], with occasional concretions of lime- 

 stone. With sufficient consistency to weather out into 

 perpendicular escarpments, this deposit forms a belt of 

 hilly country receding ten miles from the river, and then 

 changing into a stiff clay which may be part of the 

 " drift." The low alluvial lands lie on what is termed the 

 ** bottom prairie," generally a dark tenacious clay, often 

 containing concretions of bog-iron, and rarely beds of 

 sand. 



From the early part of last century lead and iron have 

 been worked in Missouri. The mining industry of the 

 State has gradually developed, and is now making rapid 

 progress. In the year 1872, 13,550,135 pounds of lead 

 were produced in the State. During the first six months 

 of 1874, 5,050 tons of pig-lead were sent by railway into 

 St. Louis. The yield of iron and zinc is likewise steadily 



increasing. Vast quantities of sulphate of baryta are 

 said to be raised, and to be used in the improvement 

 (that is, the adulteration) of white lead. A territory so 

 richly stored with mineral wealth ought to be able to 

 equip and maintain a sufficient staff for the thorough 

 exploration of the geological and mineralogical structure 

 of the ground, and for the formation of a museum where 

 the rocks, minerals, fossils, and manufactured mineral 

 products may be displayed, and made practically useful 

 and instructive. Arch. Geikie 



OUR ASTRONOMICAL COLUMN 



Dun Echt Observatory Publications, Vol. II. — 

 In this handsomely-printed volume of two hundred pages 

 we have the first portion of results of observations made 

 during Lord Lindsay's expedition to the Mauritius on the 

 occasion of the late transit of Venus, an expedition which 

 for the care and forethought bestowed upon the arrange- 

 ments and the excellence and completeness of the equip- 

 ment, compares favourably with any of those fitted out by 

 the various Governments which took part in the observa- 

 tion of this rare phenomenon. 



It was upon the strong recommendation of the eminent 

 Secretary of the German Transit of Venus Commission , 

 Prof. Auwers, that Lord Lindsay was induced to take out 

 a heliometer, and an instrument of this class, similar to 

 those intended to be used in the Russian expeditions, was 

 ordered in the spring of 1872 and completed in due time 

 by the joint exertions of Messrs. Repsold, of Hamburg, 

 and Messrs. Cooke and Sons of York. In the investiga- 

 tion of the constants of the instrument previous to- the 

 expedition, experience was obtained of the great precision 

 to be attained in the measurement of angular distance 

 between two stars by its means, and this experience led 

 to a determination to take advantage of a near opposition 

 of the minor planet Juno, occuriing during the anticipated 

 period of residence at the Mauritius, to investigate the 

 solar parallax, from the diurnal parallax of the planet, by 

 measuring its distance and angle of position with respect 

 to a star, both morning and evening. On November 4 

 Juno in perigee was distant 1029, and though the paral- 

 lactic displacement in such case is considerably less than 

 in a transit of Venus, or an opposition of Mars, it was 

 believed that the great accuracy attained in measures 

 with the heliometer would more than compensate for this 

 disadvantage. 



Vol. ii. of the publications of Lord Lindsay's Observa- 

 tory is devoted to the .discussion of the observations of 

 Juno, preceded by a very detailed account of the instru- 

 ment and its adjustments and of the methods adopted in 

 determining its instrumental errors, as errors of scale 

 divisions and errors of screw and of the method of obser- 

 vation and calculation of instrumental results. And in 

 the event of criticism of any of the processes it must be 

 stated that the whole of the work is so presented as to 

 admit of future discussion, with any modification of plan 

 that may be deemed advisable. It was originally intended 

 that the observations should commence on October i o 

 and continue to the end of November. Circumstances, 

 however, prevented so long a series of measures ; Lord 

 Lindsay's yacht with the instruments did not arrive at the 

 Mauritius until November 2, and it was not till November 

 10 that the first heliometric observations could be made. 

 The first reliable series was obtained two evenings later, 

 and from this time to November 30, observations were 

 secured on twelve evenings and eleven mornings, some of 

 them not being so complete as was desirable. It will thus 

 be seen that Juno was past opposition before work 

 could be commenced, and this first attempt to determine 

 the solar parallax, through measuring the diurnal parallax 

 of a minor planet with the aid of the heliometer, was con- 

 sequently made under less favourable conditions than may 



