I propose that cones don't require sea salt water to live in.
I generally support the find of a cone in the lake and rationalize the following.

Lake Worth has various chemicals dissolved within.
It isn't sea salt, whatever that is.  It depends were you are as to what salts
are  available.  For the most part, it is NaCl. But in chemical terms 'salts'
are dissolved.
Lake Worth has the following chemicals.  (projected and not from the water company)
Some are CaCo3, Iron oxides, Phosphates, Chlorates, lawn chemicals and a few more.
The worst are inorganic from fuels, oils and what was used to kill stuff and
inhibit growth.

The fish issue is buoyancy.  The lake isn't pure distilled water.
I suspect cones can live in various places since they don't swim and don't
need  fine touch on their body buoyancy as fish do.
Fish inflate and deflate bladders as they swim through differing salinity layers
of sea water.

Cones just move about in the sand and upon structure.
I think the only issue would be a chemical that would harm their oxygen
absorption parts or other body parts. The carbonate might be a buffering
solution that both protects and aids in shell production.
Winter cold might force them deeper into the lake but there is depth.

* I think what we need is someone that has access to an abundance of cones
(grow them in a lab?) from the ocean, take a few and place them in fresh water
as a test.
If that fails or at the same time, test then into a water with lime.
The cones were said to be found in the lake.
We need to determine the feasibility and he process that allowed that habitat.

* A study like this might help in relocating mollusks from a threatened home to
   another site to live.  Transportation and maintenance might be easier before
   placing in a new habitat.

Lake Worth is a water supply, sporting location with house boats and the like.
It is located just north of Fort Worth - "The gateway to the west" several hundred
miles from the Gulf of Mexico and 30 miles, more or less, West from Dallas.
It is lying in limestone and granite beds of rock.  The limestone from the days
when it was covered by ocean, the granite from various uplifts and volcanic
structures.

Martin

On 9/26/2010 10:08 AM, Peggy Williams wrote:
> Martin: do you understand that "Lake Worth" is really a salt water estuary?
>
> Peggy
>
> On Sep 25, 2010, at 7:08 PM, Martin H. Eastburn wrote:
>
>> My thoughts if they were in the keys and lived in shallow water -
>> they might take brackish water. The brackish is from heavy rain and runoff.
>
>

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