354 Geological Survey of the State of Ohio. 



from an investigation of the zoology and botany of Ohio. From 

 it we make but a single extract. 



"By knowing the habits of insects, we can often obviate their attacks. 

 The farmer may find it advantageous, in those sections of the state where 

 the Hessian fly is common, either to postpone sowing his seed until the 

 time for depositing the egg of the insect has passed, or to substitute spring 

 for winter wheat ; and it is also probable that some of the winter varieties 

 of this grain may yet be found with stalks so solid that they will resist the 

 attacks of this enemy. Many years since, the timber in the navy yards 

 of Sweden was rendered unfit for use by the perforations of a small worm. 

 The government applied to Linnseus for a preventive of its attacks. He 

 recommended to have the timber sunk in water during the k\v days that 

 were occupied by the insect in depositing its eggs. The remedy was 

 perfectly effectual; and, simple as it was, saved more than a million of 

 dollars annually to his country." pp. 68, 69. 



The report of Mr. Briggs embraces all the economical facts col- 

 lected by him and Mr. Foster, on the detailed survey of the south- 

 ern portion of the State. There is an accompanying section to 

 illustrate the superposition of the rocks between the great lime- 

 stone deposit and the upper part of the coal series. 



With respect to geological sections, says De La Beche, too 

 much stress cannot be laid on the importance of rendering 

 them as conformable to nature as circumstances will admit : that 

 is, the perpendicular elevations and base lines should be, as much 

 as possible, in proportion to each other. Without this necessary 

 precaution, such sections are little better than caricatures of na- 

 ture, and are frequently much more mischievous than useful, 

 even leading those who make them to false conclusions, from the 

 distortions and false proportions of the various parts. * * * 

 It is clearly in the interest of science that they should be what 

 they pretend to be, miniature representations of nature.* To 

 this section we have three objections. 1. The strata are indi- 

 cated without reference to relative thickness. 2. They are 

 represented as nearly horizontal with a uniform dip of 80 feet 

 per mile, whereas they are more or less undulating. We think 

 that these physical features of the country could have been 

 indicated on the section. Our third objection is of a more serious 

 character. The conglomerate is erroneously represented as ex- 

 tending nearly to Bainbridge ; whereas the outcrop of the con- 



* Geol. Manual, Phila. ed. 1832, p. 519. 



