This is a two stages cache. At stage one you will find a Historical Marker read this to gather the information on where the final stage and physical cache and log is located. There will be three years on the marker you will need to gather the numbers
N31°28.8_ _
How many sheep herders were there? place this number into the first slot of the coordinates
The third year - take the third number and place into the next slot giving you the first part of your coordinates
W98°53.9_ _
The second year- take the last number and place into the first slot of the coordinates
The first year - take the second number and plug into the last slot.
Stage Two you will see a head stone with Lovelace very close by.