MARYLAND GEOLOGICAL SURVEY 161 



storms, which often occasion heavy downpours over limited areas during 

 brief periods of time, while in winter, rains are general over the State, 

 and are necessarily less in amount. 



For further details in regard to the climate of St. Mary's County, 

 reference is made to the following brief sketch of the Climatology of 

 Charlotte Hall. 



THE CLIMATOLOGY OF CHARLOTTE HALL 



Latitude, 38° 28' N.; longitude, 76° 47' W.; elevation, 167 feet. 

 Observer, Prof. J. Francis Coad, 1893 to 1904. 



INTRODUCTORY. 



The station is situated in the northwest portion of St. Mary's County 

 in the region of the greatest elevation of the land, on the line of the 

 Washington, Potomac, and Chesapeake Eailway. It is on a level plateau 

 of considerable extent, lying between the headwaters of Trent Hall Creek 

 and Gilbert Swamp. An exact description of the position of the instru- 

 ments cannot be given ; they were probably suitably located in the vicinity 

 of the school in which Prof. Coad was an instructor. At present the 

 instruments are exposed in a standard shelter in the garden south of 

 the rectory of Trinity Glebe, about two miles from Charlotte Hall. The 

 shelter is over sod, and the door opens towards the north ; the thermome- 

 ters are about 4 feet from the ground. The nearest woods are about 

 400 feet south of the shelter, and there are no large bodies of water in the 

 vicinity. 



For the convenience of the investigator it is advisable to adopt a 

 uniform method of presenting the statistical material available for im- 

 portant individual stations, where this is possible. For Charlotte Hall 

 records are available for 109 months, or 9 years, but observations were 

 not continuous throughout each year, except in 1895, 1897, 1898, and 

 1900. The main features of the climate of this station are presented 

 in the meteorological summary by months in Table XIV. Other details 

 are given in the usual manner, in Tables XV to XXIII. 



