Here is my array:

{latlng: [{lat: 41.9841092242239, lng: -87.6459866168}, {lat: 41.948650308164744, lng: -87.64431828280067}, {lat: 41.94833112697515, lng: -87.644017875391}]

Here is my javascript code:

  var postedData = JSON.stringify({
                latlng: boundaries
            });

            alert("here are your boundaries so far : " + postedData);

            $.ajax({
                url: '/Communities/UpdateBoundaries',
                type: "POST",
                traditional: true,
                contentType: "application/json",
                data: postedData,
                datatype: "json",
                success: function () {
                    console.log('success!!');
                }
            });
        }

and here is my controller: where boundaries is my incoming array of latlng, but it is coming in null.

   [HttpPost]
    public ActionResult UpdateBoundaries(List<latLng> boundaries)
    {
        return View();
    }