Yes. I have found the option for measuring the depth using Garmin Fishfinder 350C. You can easily measure the depth using option full screen (select 1). Before getting depth you have to set properties whether you are measuring depth in Freshwater or salt water.
I have tried the Garmin 350C Fish Finder in the field. You have to choose the data display screen. It will give the point data, not the continuous one like the echo sounder. However, it works well even in the marine environment if you set the range well. If you buy the Fishfinder with SD card, then it can store data.